From: "Stuart Slade"
Date: Mon Aug 19, 2002 07:53:22 AM US/Pacific
Subject: Nuclear Warfare 101

The Nuclear Game - An Essay on Nuclear Policy Making

When a country first acquires nuclear weapons it does so out of a very accurate perception that possession of nukes fundamentally changes it relationships with other powers. What nuclear weapons buy for a New Nuclear Power (NNP) is the fact that once the country in question has nuclear weapons, it cannot be beaten. It can be defeated, that is it can be prevented from achieving certain goals or stopped from following certain courses of action, but it cannot be beaten. It will never have enemy tanks moving down the streets of its capital, it will never have its national treasures looted and its citizens forced into servitude. The enemy will be destroyed by nuclear attack first. A potential enemy knows that so will not push the situation to the point where our NNP is on the verge of being beaten. In effect, the effect of acquiring nuclear weapons is that the owning country has set limits on any conflict in which it is involved. This is such an immensely attractive option that states find it irresistible.

Only later do they realize the problem. Nuclear weapons are so immensely destructive that they mean a country can be totally destroyed by their use. Although our NNP cannot be beaten by an enemy it can be destroyed by that enemy. Although a beaten country can pick itself up and recover, the chances of a country devastated by nuclear strikes doing the same are virtually non-existent. [This needs some elaboration. Given the likely scale and effects of a nuclear attack, its most unlikely that the everybody will be killed. There will be survivors and they will rebuild a society but it will have nothing in common with what was there before. So, to all intents and purposes, once a society initiates a nuclear exchange its gone forever]. Once this basic factor has been absorbed, the NNP makes a fundamental realization that will influence every move it makes from this point onwards. If it does nothing, its effectively invincible. If, however, it does something, there is a serious risk that it will initiate a chain of events that will eventually lead to a nuclear holocaust. The result of that terrifying realization is strategic paralysis.

With that appreciation of strategic paralysis comes an even worse problem. A non-nuclear country has a wide range of options for its forces. Although its actions may incur a risk of being beaten they do not court destruction. Thus, a non-nuclear nation can afford to take risks of a calculated nature. However,a nuclear-equipped nation has to consider the risk that actions by its conventional forces will lead to a situation where it may have to use its nuclear forces with the resulting holocaust. Therefore, not only are its strategic nuclear options restricted by its possession of nuclear weapons, so are its tactical and operational options. So we add tactical and operational paralysis to the strategic variety. This is why we see such a tremendous emphasis on the mechanics of decision making in nuclear powers. Every decision has to be thought through, not for one step or the step after but for six, seven or eight steps down the line.

We can see this in the events of the 1960s and 1970s, especially surrounding the Vietnam War. Every so often, the question gets asked "How could the US have won in Vietnam?" with a series of replies that include invading the North,extending the bombing to China and other dramatic escalations of the conflict. Now, it should be obvious why such suggestions could not, in the real world, be contemplated. The risk of ending up in a nuclear war was too great. For another example, note how the presence of nuclear weapons restricted and limited the tactical and operational options available to both sides in the 1973 Yom Kippur War. In effect neither side could push the war to a final conclusion because to do so would bring down nuclear attack on the heads of the "winners". Here, Israel's nuclear arsenal was limiting the conflict before it even started. Egypt and Syria couldn't destroy the country - all they could do was to chew up enough of the Israeli armed forces and put themselves in the correct strategic position to dictate a peace agreement on much more favorable terms than would be the case. But, the Israeli nuclear arsenal also limited the conflict in another way. Because they were a nuclear power they were fair game; if they pushed the Egyptians too hard, they would demand Soviet assistance and who knew where that would lead?

So, the direct effects of nuclear weapons in a nation's hands is to make that nation extremely cautious. They spend much time studying situations, working out the implications of such situations, what the likely results of certain policy options are. One of the immense advantages the US had in the Cold War was that they had a network of Research Institutes and Associations and consulting companies who spent their time doing exactly this sort of work. (Ahh the dear dead days of planning nuclear wars. The glow of satisfaction as piecutters are placed over cities; the warm feeling of fulfillment as the death toll passed the billion mark; the sick feeling of disappointment as the casualties from a given strategy only amounted to some 40 million when preliminary studies had shown a much more productive result. But I digress). This meant that a much wider range of policy options could be studied than was possible if the ideas were left in military hands.These organizations, the famous think tanks had no inhibitions about asking very awkward questions that would end the career of a military officer doing the same. This network became known as The Business. We're still out here.

So. What were nuclear weapons good for? It seems they are more of a liability than an asset. To some extent that's true but the important fact remains,they do limit conflict. As long as they are in place and functional they are an insurance policy against a nation getting beaten. That means that if that country is going to get beaten, its nuclear weapons have to be taken out first. It also means that if it ever uses its nuclear weapons, once they are gone, its invulnerability vanishes with it. Thus, the threat posed by nuclear weapons is a lot more effective and valuable than the likely results of using those weapons. Of course, this concern becomes moot if it appears likely that the NNP is about to lose its nuclear weapons to a pre-emptive strike. Under these circumstances, the country may decide that its in a use-it-or-lose-it situation.The more vulnerable to pre-emption those weapons are the stronger that imperative becomes.

This is why ICBMs are such an attractive option. They are faster-reacting than bombers, they are easier to protect on the ground and they are much more likely to get through to their targets. This is why modern, advanced devices are much more desirable than the older versions. In the 1950s the Soviet Union had a nuclear attack reaction time of six weeks (don't laugh, that of the US was 30 days). The reason was simple, device design in those days meant that the device, once assembled, deteriorated very quickly and, once degraded, had to be sent back to the plant for remanufacture. Device assembly needed specialized teams and took time. This made a first strike very, very attractive - as long as the attacker could be sure of getting all the enemy force. It was this long delay to get forces available that made air defense and ABM such an attractive option. In effect, it could blunt an enemy attack while the assembly crews frantically put their own devices together and got them ready for launch. As advancing device design made it possible to reduce assembly time, this aspect of ABM became less important.

What this also suggests is that large, secure nuclear arsenals are inherently safer than small, vulnerable ones. A large arsenal means that the owner can do appalling damage to an enemy, a secure arsenal means that no matter how the enemy attacks, enough weapons will survive to allow that destruction to take place. Here we have the genesis of the most misunderstood term in modern warfare - MAD, Mutually Assured Destruction. (Another point of elaboration here - MAD is not a policy and has never been instituted as a policy option. It's the effect of policies that have been promulgated. This is a very useful touchstone - if people mention the US Policy of MAD, they don't know what they are talking about). Its widely believed that this suggests that both sides are wide open to unrestricted destruction by the other. This is a gross over-simplification. What the term actually means is that both sides have enough nuclear firepower to destroy the other and that the firepower in question is configured in such ways that no pre-emptive strike can destroy enough of it to take away the fact that the other country will be destroyed. MAD did not preclude the use of defensive systems - in fact it was originally formulated to show how important they are - but its misunderstood version was held to do so - with catastrophic results for us all. One implication of this by the way is that in spite of all the fuss over the Chinese stealing the W88 warhead design, the net beneficiary of that is the United States; it allows the Chinese to build a much more secure deterrent and thus a more stable one. Also, looking at things purely ruthlessly, its better for one's enemy to make small clean bombs than big dirty ones.

Aha, I hear you say what about the mad dictator? Its interesting to note that mad, homicidal aggressive dictators tend to get very tame sane cautious ones as soon as they split atoms. Whatever their motivations and intents, the mechanics of how nuclear weapons work dictate that mad dictators become sane dictators very quickly. After all its not much fun dictating if one's country is a radioactive trash pile and you're one of the ashes. China, India and Pakistan are good examples. One of the best examples of this process at work is Mao Tse Tung. Throughout the 1950s he was extraordinarily bellicose and repeatedly tried to bully, cajole or trick Khruschev and his successors into initiating a nuclear exchange with the US on the grounds that world communism would rise from the ashes. Thats what Quemoy and Matsu were all about in the late 1950s. Then China got nuclear weapons. Have you noticed how reticent they are with them? Its sunk in. They can be totally destroyed; will be totally destroyed; in the event of an exchange. A Chinese Officer here once on exchange (billed as a "look what we can do" session it was really a "look what we can do to you" exercise) produced the standard line about how the Chinese could lose 500 million people in a nuclear war and keep going with the survivors. So his hosts got out a demographic map (one that shows population densities rather than topographical data) and got to work with pie-cutters using a few classified tricks - and got virtually the entire population of China using only a small proportion of the US arsenal. The guest stared at the map for a couple of minutes then went and tossed his cookies into the toilet bowl. The only people who mouth off about using nuclear weapons and threaten others with them are those that do not have keys hanging around their necks. The moment they get keys and realize what they've let themselves in for, they get to be very quiet and very cautious indeed. Another great - and very recent example - look how circumspect the Indians and Pakistani Governments were in the recent confrontation - lots of words but little or no action to back them and both sides worked very hard not to do anything that could be misunderstood. (When the Pakistani's did a missile test they actually invited the Indians over to watch in order to ensure there was no ground for misunderstanding. The test itself was another message from both countries to the rest of the world - basically it read "Don't sweat it, we know the rules")

One analyst from The Business was asked what Saddam Hussein would have done if Iraq had possessed nuclear weapons in 1990. He replied that he didn't know what he would have done but he did know what he would not have done - he would not have invaded Kuwait.

From: "Stuart Slade"
Date: Tue Aug 20, 2002 07:41:34 AM US/Pacific
Subject: Nuclear Warfare 102

The Nuclear Game (Two) - Targeting Weapons

One of the interesting aspects of a nuclear war is planning how its going to be done. Most fictional accounts of this process seem to assume that cities will be the primary targets and there will be one device allocated per city. This is very far from the truth. In fact, nuclear attack plans are very complicated things and, in a quite real sense, they don't exist. What does exist is a whole series of strategies aimed at achieving specific results. Which of those strategies are adopted and in what combinations is determined by the specific events taking place. Very often we'll hear of people talking about "The SIOP" as the Holy Grail of the US nuclear war plans. A good touchstone because there is no such thing - if people claim to have worked on the SIOP, they are being economical with the truth. What does exist are a very large number of plans and options that are put together on a mix-and-match basis.

Unfortunately planning a nuclear strike isn't just a matter of working out which cities to destroy. In fact it isn't even a matter of working out which cities to destroy. In fact, we don't target cities at all per se. We target things, some of which happen to be in cities. Its necessary to remember the key; nuclear weapons are a tool, no more, no less. We don't blow up cities just because they are there any more than we fix a TV antenna on the roof by digging a hole in the back garden.

Since we are using a tool to do a job, the first stage is to work out a series of objectives (ie decide what that job is). Normally discussions of such things rotate around strategies being either counter-force or counter-city but its a lot more complex than that. At the last count there were about 30 distinct targeting strategies that could be adopted. As an example, there could be:-

Counter-military - aimed at destroying a country's armed forces. Such a strike would be aimed at things like arsenals, ports, airbases, military training sites etc

Counter-strategic - aimed at taking out a country's strategic weapons force. This would hit the ICBM silos, SSBN ports and bases, the SSBNs themselves, bomber bases, nuclear storage depots etc.

Counter-industrial - aimed at destroying key industrial assets and breaking the target country's industrial infrastructure

Counter-energy - aimed at destroying a country's energy supplies and resources plus the means for distributing them.
Counter-communications - aimed at disrupting and eliminating the target country's communications (radio, TV, landline, satellite etc)communications systems.

Counter-political - aimed at erasing the target country's political leadership - note this is MUCH more difficult than it seems and is very dangerous. Killing the only people who can surrender is not terribly bright

Counter-population - aimed at simply killing as much of the enemy population as possible. A very rare strategy.

There are plenty of others. One of the things that gets done at this level is to think up targeting strategies, work out the target sets associated with that strategy and the resources needed to eliminate that target set. Based on that we can then work out if that particular target strategy is an effective use of resources. Note also that adopting one particular target strategy does not preclude simultaneously putting another into play. Mix and match again.

So lets look at a typical targeting problem in an average sort of strike. We are going to give the capital of Outer Loonyistan a really thorough seeing-to. Now we don't just explode a bomb in the center of the city and say bye-bye. Believe it or not that won't do any real good. Initiate a 1 megaton device over the center of London and 95 percent of the cities assets and 80 percent of the population will survive (this means that, proportionally speaking, Londoners will be better off after a nuclear attack than they were before it took place. This was the basis of at least one Get Rich Quick scheme proposed in The Business).

So we start by selecting a specific targeting strategy. Now we have to estimate the weight of attack Asylumville is likely to come under if that strategy is adopted. To do this we first work out how high Asylumville stands with regard to other potential target areas for that particular strategy. This is usually done by a careful assessment of what targets are in that area as opposed to similar target areas in other parts of the country and assuming the available warheads are distributed according to the target density in that area. Then we assess how many warheads are likely to be inbound and crank that into the priorities we've established to see how many are likely to be fired at Asylumville. It'll be a lot fewer than you think. This means is that we have to look very carefully at the city, its geography and the distribution of its assets in order to work out how to take it down.

To do this we need some maps. We need a standard topographical map, demographic maps and asset/resource maps. Take the targeting strategy and the likely target set associated with it and plot them on that map. Now think out how hard that target set is going to be to destroy. The problems now become apparent. Some targets are best attacked by surface bursts, others by high airbursts. Some, very hard targets need almost direct hits to destroy them; others are so small (and so hard) that hitting them is very difficult.The sort of things we might look at hitting, depending how we do things, are communication facilities, railway marshalling yards, factories, oil refineries, government offices, military bases For example, if the target strategy is anti-communications,amongst the primary targets will be airfields and railway marshalling yards.They are notoriously difficult to destroy, the attacker needs big warheads and needs to ground burst them so the target is physically scoured from the ground. There is a lot of thought needed here; you'll find there are far more potential targets than real warheads so you'll have to allocate the warheads one way, then try to work out the effects. To give you some idea of how that list grows, there are something like 50,000 priority nuclear targets in Russia. Some of them are weird and tucked right out of the way (one of the most critical non-military targets in the USA is where you would least expect it). Now many of that 50,000 target list will be virtually on top of eachother. One initiation will get several of them. That pulls the list down immensely, probably to around 3,000 - 5,000 targets.

OK back to working over Asylumville, the capital of Outer Loonyistan. If its like most other capitals, it'll probably merit a total of between five and ten devices to take out all the things we want to. One of the key tools used here is a thing called a pie-cutter. Its a circular hand-held computer. You set the verniers on it to the specifics of the weapon used (altitude of burst, yield etc) and it gives you a series of rings that show the various lethal effects of the bomb to certain distances. Put it down on the planned impact point and you'll get what the bomb will do. You won't get a pie cutter (they are classified equipment) but you can make your own from publically available data using tracing paper and compasses. . We end up with a map of the city after being worked over. Normally, at this point somebody says. Dammit we didn't get [insert some key assets] and we start again. The first shot at targeting will be stunningly disappointing so you play games with warhead types and yields and with burst locations until you get as many of target set as you can. Take that marshalling yard; sounds easy doesn't it? Believe me railway marshalling yards are a whirling son of a bitch to take down. They are virtually invulnerable to airbursts; we have to groundburst a blast directly on the yard. 800 yards outside and you might as well not have bothered. The problem is those yards are not that big. So now we have a problem called CEP. This stands for Circle of Equal Probability (NOT Circular Error Probable which is a totally meaningless term invented by those of the intrepid birdmen). This is a measure of the accuracy of the missile and is the radius of the circle that will contain half the missiles aimed at the center of the circle. That means that half the inbounds will fall outside that circle. Now we have a second concept; the radius of total destruction, the radius within which everything is destroyed. Its astonishingly small; for a 100 kt groundburst its about 800 yards (now see where the marshalling yard came from).. Now if the RTD exceeds the CEP we're probably OK, if it doesn't (and in most cases it doesn't) we've got problems.

What all this ends up with is we have to fire multiple warheads at single targets in order to be sure of getting them. This is a complex calculation since the optimum number of warheads for Asylumville will depend on the attack pattern and priorities. But we'll eventually end up with number that represents the best compromise between destructive effects and warhead use. To estimate the effects on the area as a whole, take the demographic map, plot the event points, altitudes and yields on that map and apply the pie-cutter set for overpressure. The overpressure needed to destroy various types of building are public record (US houses are very very soft and vulnerable) so you know roughly what will be destroyed up to a given distance. Note that the blast circles will overlap in some places. Blast also isn't logical; ground irregularities will funnel it is some directions so that an area close in may be unscathed while others much further away will be flattened.

Now we have to get them there. Missiles are not terribly reliable and a lot can go wrong. A Rectal Extraction figure suggests that only about 60 percent of them will work when the blue touchpaper is ignited. So we have to add extra warheads to allow for the duds. To give a feel for the sort of numbers that we're talking about, the British calculated that they needed 32 warheads to give Moscow a terminal dose of instant sunrise. In other words, the British nuclear deterrent took down Moscow and that was it.

Key point here on the efficiency of defenses. In the 1950s, the UK V-bomber fleet was assigned to hit over 200 targets in the Western USSR. As the 50's turned into the 60's the ability of the V-bombers to penetrate Soviet airspace came under increasing doubt. The UK shifted to Polaris - one submarine at sea, 16 missiles, three warheads per. Total of 48 targets assigned. But the USSR started to install an anti-missile system that was reasonably capable against the early Polaris-type missiles. So the UK modified Polaris in a thing called Chevaline. this took one warhead from each missile and replaced the load with decoys - then targeted all 16 missiles onto Moscow. ONE target. In effect, the Soviet defenses had reduced the UK attack plan from 200 targets to one. In other words, it was 99.5 percent effective without firing a single shot (bad news for Moscow but great news for the other 199 cities with targets in them)

That's why so many devices are needed - the inventory evaporates very fast. That's also why defenses like ABM are so important (and the urgency behind deploying the new US Missile Defense System). The defenses don't have to be very effective to work (although the new US system is looking good), its the complexity they throw into the planning process. As long as we can assume that if we get a warhead on its way to its target, that target is going to be hit, then planning is relatively easy and the results predictable. If, however, we can't make that guarantee; if we have to factor in a possibility - perhaps a good one - that the outbound warhead will be shot down, then planning becomes very uncertain. Now put yourself in the position of somebody planning a strike - do you wish to gamble your nation's change of survival on something that MIGHT work. Of course not. So Strategic Paralysis strikes again. A defense system doesn't have to work against an attack to be effective because it works on the minds of the people who make the decisions.

From: "Stuart Slade"
Date: Wed Aug 21, 2002 10:34:23 AM US/Pacific
Subject: Nuclear Warfare 103

The Nuclear Game - The Attack And After

So far, when discussing nuclear weapons, we've always been working under the presumption that the historical situation applies and that we won't see a nuclear exchange. Lets look at the grim side of the equation now. The sirens are going and the National Emergency system is screaming its head off. What's the world going to be like in 25 minutes time? One thing we have to make clear before we start. We're talking about the biggest cataclysm in human history. When we say things like "doing well" or "doing badly", those terms are relative. Another thing is that most people's preconceptions about a nuclear war and its aftermath are wrong. Nevil Shute Norway did the world a great disservice when he wrote "On The Beach". The skewed viewpoint represented by that novel has been perpetuated ever since. A good modern example is the so-called "nuclear blast mapper" available on the internet that purportedly shows the effects of an initiation on an input home address. It doesn't, it doesn't even come close. A third preconception we have to get rid of is that there is such a thing as a limited nuclear exchange or a flexible response. There isn't now, never has been and never will be. The reasons why are primarily a C4I set of consideration but the inviolable rule is this "One Flies, They All Fly". Any exchange, no matter how limited, will escalate out of control until both participants have used all their devices.

Any country can be divided into two parts. The "A-country" is the big cities, the industrial and population centers and the resource concentration they represent. Big cities got to be that way because they are in desirable locations,near good ports, river crossings or mountain passes. When the city goes, so does the locations. The "B-country" is everything else. In effect the A-country represents big vulnerable collections of assets gathered into single spots. The B-country represents dispersed ranges of resources spread over large areas.This is a very important distinction. The relative value of the A-country and the B-country depends on the country and society involved. However one thing is constant, the support and supplies that the A-country needs to survive comes from the B-country. Given time, the B-country will rebuild the A-country. The survival of the B-country is, therefore, critical while the survival of the A-country might not be. Now, the primary asset of the B-country is its population; they are the ones who will generate resources from the B-country and turn them into product. So, the critical thing for a post nuclear environment is population. Save as much of that as we can and we're a jump ahead. That sounds eminently humanitarian. In reality it has awful consequences but we'll come to those later.

The extent to which the A-country can be rebuilt and the speed with which that can be achieved depends on the damage inflicted on the cities. One of the preconceptions that plague discussion of a nuclear war aftermath is the assumption that the cities will be totally destroyed write-offs but, in reality, the situation is by no means so simple. There's a few things that are important here. One is that big devices are a rarity. There are no 100 megaton devices, very few 25 and 10 megaton devices and not all that many 5 megaton weapons. The largest devices in widespread use are 1 megaton weapons and the majority of strategic weapons are in the 350 -150 kiloton bracket. 50 kiloton strategic weapons are quite common. The reason is quite simple. The destructive power of an explosion is distributed in three dimensions (actually four since the time component is very important) so the destructive power of a device is directly proportion to the cube root of its explosive power. Even worse, the destructive effects of a device are like many other distance related phenomena; they obey the inverse square law. Double the distance from the blast center and the effects are reduced by a factor of four. Therefore, a 1 megaton device is not 1,000 times as destructive as a 10 kiloton device, its ten times as such and those effects attenuate rapidly with distance. However, very big devices are MUCH heavier than small ones and consume disproportionate amounts of fissile material. Put all this together and its much more productive to have a large number of small devices than a small number of large ones.

Another is how the devices are used. The radius of destruction of nuclear devices is actually quite limited; this is a natural outgrowth of working on the inverse square law. Even with one of the "big" 1 megaton weapons, its fury is largely spent by the time the blast wave has reached ten miles from center. The smaller devices have lesser radii although the workings of the cube power rule mean that those radii are not as small as the difference in explosive power suggests. Nevertheless, the relatively limited effect of the devices shows that the general civilian presumption that ground zero for a nuclear strike on a city will be the city center is likely to be wrong. The devices will be targeted onto specific parts of the city that are judged to be of especial value. These may actually be in the suburbs or other peripheral areas.

So how does a nuclear device destroy things? The primary effects that result from the initiation of a device are (in no particular order) a light flash, a heat flash a blast concussion wave and a sleet of direct radiation. In fact, of these the last is of relatively little significance. The range of the radiation is very short and is further attenuated by the inverse square law. Its only significant within the areas where blast and heat are already lethal. If thermal blast and concussion have already reduced you to the size, shape and color of a McDonalds hamburger, irradiating you as well is incredibly superfluous. Thus the direct effects we are interested in are light, heat and blast and they do arrive in that order. The further an observer is from the point of initiation, the greater the gap between them. This is very important. The flash of light that will blind a victim close in serves to warn a potential victim further out. Once a few miles out from ground zero, the light flash tells the population that a device has gone off and its shadows show them sheltered areas from the next effects to arrive. If an area is shadowed from light, its shadowed from radiant heat as well. The heat flash is the first really destructive effect to hit. This is direct radiated thermal energy; like light it travels in straight lines. It will set anything inflammable on fire to a considerable distance from ground zero. Interestingly, it won't set non-flammable things on fire and, for example, must enter a house via windows etc before setting that house on fire. If the windows are masked (for example painted white), the heat flash is unlikely to set a brick-built house on fire (US-style frame houses are a different matter which is why it makes me uneasy living in one).

Last to arrive is blast. Unlike light and heat, both of which travel in straight lines, blast can be funneled by structures, deflected and masked. The windows we carefully painted white are history; smashed by the blast wave and its associated wave front of debris but they've done their job. The heat flash has gone. Houses are actually quite well designed to resist pressure from outside - its pressure from inside that gives them problems. Again, if you can keep the blast out you've got a good chance. Impossible close in to ground zero but progressively easier as we get further from that point. Closing the shutters on windows inside the house is good; even taping the glass in a lattice pattern is astonishingly helpful. Compared with military targets, civilian structures have relatively low damage resistance. In the jargon we've been looking at, this is called protection factor (PF) - most civilians can, with a few minutes warning give themselves a PF of around 40 - meaning they are 40 times more likely to survive than an unprotected civilian. In other words, even though the structures surrounding them are soft and weak, there is a lot they can do that will greatly increase their chance of survival. Note that - even when the sirens are going off, there is still a lot you can do that greatly increases your chances of surviving - provided you have a chance of surviving in the first place.

Lets imagine somebody has taken a serious dislike to your home town and decided to remove it. For all intents and purposes, the effects of initiation are generated in the center of the device initiation and travel outwards evenly in all dimensions to produce a perfectly symmetrical sphere or fireball. Now think of the geometry of this. If the device is initiated at ground level, a so-called ground burst, half of all that energy will go into the ground, scouring out a crater but effectively being wasted. More goes skywards. Some will be reflected down towards the earth but very little; effectively that energy too is wasted. The only energy that is actually useful is that produced in a narrow segment around the equator of the spherical ball produced by the initiation. Thus, for this type of attack ground bursts seem very inefficient. They are.

So what do we do about it? Again, think of the geometry. If we lift the detonation point into the air, the segment of the sphere that will spend its energy destroying valuable things is increased and the amount that scours out a crater gets smaller. Keep thinking along these lines and we reach a point where the sphere of the fireball doesn't quite touch the ground at all. In this case almost all the energy from the lower half of the fireball destroys valuable things and none goes to digging a crater. This is called a low airburst and it remains a low airburst as long as the altitude of the point of initiation of the device is less than the diameter of the fireball (ie there is a fireball radius between the bottom of the fireball and the ground). If the point of initiation of the device is at an altitude greater than the diameter of the fireball it's a high airburst. If the intention is to knock down cities, low airbursts are the most effective way of doing it.

We haven't mentioned fall-out. The dreaded stuff that destroys humanity.Well, there's a reason for that; the device has only just been initiated, there isn't any fall-out yet. Fall out is caused (mostly) by debris from the ground being sucked into the fireball, irradiated and spewed out of the top. This radioactive plume coalesces in the atmosphere and falls back to earth. It's a mix of isotopes of varying half lives. The most vicious of these isotopes have short half lives and are gone in a few hours (usually before the fallout makes it back to the ground). The milder ones can hang around for millennia but their effects are tolerable (speaking relatively again). The really dangerous ones are those that have a half life of between 5 and 6 years - these are long-lived enough to be seriously contaminating and hot enough to be dangerous. The worst is cobalt). Now the blast and heat throw debris outwards, where does the debris sucked into the fireball come from? Answer is the crater scoured in the ground by the energy from the device that went into said ground. But hang on, we've just discovered the best way to knock a city down is to use an airburst that doesn't crater the ground. Doesn't that mean no fallout? That's right, airbursts are relatively clean from a fallout point of view. They do generate some fallout from atmospheric dust and water vapor and a bit more (some very nasty) comes from the debris of the device but not as much as legend holds. This is especially the case since modern devices are very clean indeed and the debris from their initiation is far less than from the older designs.

All this means that dropping a nuclear device on a city doesn't necessarily destroy it. In fact, an acquaintance of mine, Peter Laurie, used to start off his lecture on such things by suggesting that 1 megaton device dropped on London would do only trivial damage to the city. After the lynch mob had been brought under control, he'd put a pie cutter on a demographic map of London and prove the point. We touched on how limited the damage caused by a one megaton device initiated over the City of London would be in Part Two. To be fair,that includes people and property slightly damaged but repairable. The catch is that London wouldn't have been hit by one but by several (in fact four 350 kiloton and two 1 megaton weapons in one particular attack plan). This would still leave a substantial proportion of the population and a larger proportion of their assets intact.

The implication of all this is that despite being subject to concentrated attack, the A-country isn't totally destroyed (although its society is) and remains a storehouse of people and goods. As an institution a big city is not viable for a variety of reasons but that is a long way from saying its simply flat, black and glowing in the dark. Its quite possible (depending on the attack patterns) that the big cities may be relatively unscathed.

So what's been going on in the B-country. One attack pattern is to hit the nuclear weapons stationed out there. These are mostly silo-based missiles. The only way to destroy those is to explode a device directly on top of the silo and scour out of the ground. In other words, a ground burst. And they create huge amounts of fallout. This means that a counter-force strike is inherently much more dangerous to the survival of the population than a counter city strike. Weird isn't it? A counter-value strike attacking the population in their home cities gives them a reasonable chance of survival while a counter-force strike restricting the target plan to military targets and rejecting a deliberate attack on the cities radically decreases that chance of survival. It's a point we've seen happening over and over again - when dealing with nuclear weapons we often end up going places we never thought we would. Thats because the logic behind nuclear weapons use and the effects of that logic is often counter-intuitive. It also demands careful though and examination of reality, not preconceptions or postures. The B-country also gets hit by counter-city strikes but the dispersed nature of the population reduces their direct effects.

OK so its over. The devices have ceased to arrive and eventually, probably after some 36 to 48 hours the all clear sounds. Notice another thing here; most accounts (The Day After for example) of a nuclear attack have a spasm lasting a few minutes and thats it. Sorry, Ain't So. The exchanges go on for days.

What happens now? From now on we're looking specifically at the USA. We have to get the B-country working again. As we touched on earlier, the cities are not viable places to live. Without their support infrastructure, they will become plague pits and charnel houses - just like the cities in 1632 :) . They have to be evacuated and the people distributed in the B-country to make up for losses there. In the B-country people are ambling around with Geiger counters plotting what's hot and what isn't. At this point life gets grim. We triage the population. One triage is condition. Who cannot be saved and will be left to die, who can only be saved with massive (and probably impractical) effort, those who can be saved with the means available now (the ones who get priority) and who will recover without treatment. On top of this is another triage. The population is prioritized according to need for protection. Pregnant women and children are top, young women of childbearing age second. Young men third, older men fourth, old women bottom. This is ruthless and brutal but its essential for survival. Given a choice between saving a young woman who can bear children and an old woman who cannot, we save the potential mother. We do the same with food. Food and water are checked for radioactivity. The clean food goes to the children and young women, the more contaminated food to the lower priority groups. That old woman? She gets the self-frying steaks.

In this situation the US has a terrific advantage over the rest of the world. Its called the Second Amendment. The B-country population is largely armed, sometimes quite heavily. They do exactly what Founding Fathers envisaged - provide a body of armed people whom the local authority can assemble to maintain order. (The Supreme Court may argue that interpretation of the Second Amendment but by now they are doing so with the people who wrote it). In a more general sense, post-holocaust fiction usually has gangs of outlaws preying on the defenseless citizenry. Interestingly that doesn't seem to happen. In disasters people tend to work together rather than against eachother (for example in US urban disasters Hells Angels biker gangs have made sterling contributions to relief efforts using their bikes and riding skills to get emergency supplies through to places others can't). While lawlessness and disorder do occur, the ease of forming a civilian militia (using the term properly here meaning something very much like the Sheriff?s Posse beloved of Westerns) brings that situation under control. Other countries are unlikely to be so fortunate.

So we're in a race. Can we rebuild the B-country so that its firstly self-sustaining without the services provided by the A-country while the stockpile of pre-attack assets survive. Can we reconstruct a working society fast enough so that we can feed enough people to keep going? Can the surviving women bear enough children (and survive doing so) to replace the death toll. For the loss won't stop with the attack. Diseases we consider trivial today, measles, chickenpox, influenza, will be mass killers. No medical treatment. Unless your lucky enough to be where some medical facilities have survived, a broken leg that gets infected is likely to be a death sentence. Its possible to look on this world as a 17th century US colonial environment and there's a lot of truth in that. The downside is that the colonial pioneers didn't have the decaying charnel houses of the cities to worry about. This is another key thing to bear in mind; many more people will die after a nuclear exchange and will die in it. Eric was quite correct in making his Doctor fear disease more than any other factor - its a thing that worried everybody looking at post holocaust (and now you know why the US has such well-equipped clinics tucked away in remote places).

Winning that race is vital. Lose and we're extinct. The population drops like a stone as disease, radiation and injury take their toll. Then, it should bottom out and start to recover. Teams of older men and infertile women go to the cities to recover what they can. The radiation levels continue to drop. Fortunately we don't have to worry about nuclear winter, that's been largely discredited (the atmospheric models that were used were far too simplistic and the reality seems to be we may actually get a more temperate and less changeable climate out of things - somebody once described it as a Nuclear Autumn). The ozone layer also won't be a problem - it'll regenerate fast enough and the effects of the bombs may actually be beneficial.

The ugly side of life continues. Abortion and contraception are likely to be highly illegal. We MUST have those babies. There will be more than enough parents who have lost their own (or have received too high a radiation dose to chance the FLK problem) to look after any that are unwanted. Women are enslaved by their reproductive systems again. Don't like that but there is nothing we can do about it. The social pressure on women to have children will be immense in both material and moral senses. Women who can have children get the best of everything, the cleanest and best food, the most comfortable housing, the most careful protection. Women who can have children but refuse to do so will be social outcasts (and in this sort of society to be an outcast is virtually a death sentence). We're likely to see a situation where women of childbearing age are "protected" by severe restrictions ("don't go outside the house, the radiation may harm your babies" gets abbreviated to "don't go outside") . This is a grim and disturbing picture; we take an old woman out of her house and throw her in the snow to provide shelter for a pregnant mother and her children - then lock her in. Newborn babies obviously damaged by radiation are likely to be killed on the spot. That may or may not be justifiable but I think its inevitable.

No electricity, limited medicine, almost no dentistry, no travel - we really are back to the middle ages. The fallout patterns and other things shift so its likely we'll see communities having citadels they can retreat to if necessary. Gasoline runs out cars will go; we're back to horses for transport. Fortunately we don't need factories to make more horses. Justice by the way is run by Judge Lynch. Don't expect to attack a woman and survive. Guns are also a declining asset. As the ammunition runs out we'll be making weapons in blacksmiths shops. Its interesting to see what the designers will come up with, using modern know-how with 17th century assets. We'll probably see bows and arrows come back into fashion - and that means metal body armor.

Eventually when conditions permit, our new society moves back to rebuild the A-country. It'll be a long, long time before there is another Federal Government(such things need technology to survive - a calculated guess is that it would take two centuries before a powerful central government evolved again - if it evolves again).