Ok, a little about inertial electrostatic confinement:
Basically, the idea behind IEC is like the idea behind all other
plasma confinement theories: keep the hot stuff in one place long enough
for fusion.
Not very informative, huh? Well, the most popular method of confining a 
fusion plasma is through magnetic fields. Plasmas have electric charge
and as such can easily be manipulated with electromagnetic devices. 
Plasma doesnt like to be squeezed- a large number of protons in there, 
and they all repel each other. To get pas this problem an incredible
amount of energy is required. 
While many people like magnets, mostly because it is easy to build and
control them, and also because large magnets (and thus large reactors) 
are feasible, I tend to side with a small group of physicists who believe 
that confinement with electric fields will yield more promising results. 

The main idea behind a typical IEC device is this:
The device consists of an evacuated sphere. 
In the center of this sphere is a grid, negatively charged.
Plasma is introduced and is attracted to the grid. 
The grid is mostly transparent and the plasma, which has been accelerated
from many directions in the chamber toward the center by the grid,
now passes through the grid (mostly) and meets other plasma in the center 
of the (spherical) grid. 
The accelerations and densities of the plasma, which is copressed using its
own inertia toward the center of the chamber, is sufficient to induce 
fusion reactions in the plasma.

The primary idea is that the inertia of the plasma does the work of
providing the collision energies requisite for fusion. Electric 
attraction/repulsion provides a means by which to impart this inertia.


A picture of the interior of an IEC device in opration:


There have been some variants over the years, most intriging and unique in
my opinion was a device which induced fields inside the plasma itself and
caused the plasma to deform itself through centripetal force and compress. The
idea was, ironically, developed by a fellow Greek, who died before his work 
got any further, but the device was not very successful to begin with. 
Still, I think it is cool. 
A lot of people are talking about linear versus spherical IEC devices,
but i think the idea is not yet mature. A sphere makes a very efficient
reactor for experimental purposes, but the linear devices will be more practical
when the technology is ready to be considered for real-world applications. 

My own ideas concern the possibility of holding the plasma in the reactor
for very long periods of time by use of fluctuating or even alternating fields.
Frequency of alternation would be optimized to two goals:
one, to allow the plasma to stratify accordign to composition, i.e. with 
larger nuclei most probably ion ash from previous reactions, to settle on the
surface of the plasma and possible be ejected from the plasma in the 
interval,
 and two: to take advanntage of natural resonances and produce harmonic
oscillation inside the plasma. Heating and thus fusion reactions would be 
much more probable. 

Electric fields are a nice way to work with plasmas because they clearly 
set up a potential gradient, whereas magnetic confinement sets up accelerations
and causes a lot of turbulence in the plasma which interferes with fusion
reactions at localized places and leads to great instability in the plasma.
At the large reactors at Princeton and Berkely, for example, the longest
running times are on the order of 10^1 seconds. IEC devices have been able to 
confine stable plasmas for times on the order of 10^3 seconds. 

Another factor is scale: Magnetic confinement devices generally work 
better with larger plasmas and reactors- one reason for this is the great
deal of accelleration the plasma itself experiences and the currents within
it that must be dealt with. The TFTR at princeton, so far the most successful
Tokamak, is the size of a small house, whereas IEC devices are as small as 
a few inches in diameter. Though they are typically many orders of magnitude
away from a breakeven ( energy in = energy out ) IEC devices are used today
mostly to burn D-T as cheap neutron sources. 

The single biggest problem with these devices is that they work on very
sparse plasmas: they concentrate almost pure ions in the center
of the device and thus must be of very low density to have such 
stability with such complete separation. By some schools of thought, this
concentration doesent classify as a plasma, since (obviously for the device
to funciton) the plasma is of suc composiiton and configuration that
its Debye length (effective radius of charge separation without a reactive
counter-separative field being set up) is very large compared to the total
size of the plasma. However, the device does accelertae them sufficiently
to overcome Coluomb repulsion between the ions and initiate fusion
anyways, which is impressive.
Another idea which I have thought interesting was that of a ring charge,
a sort of a toroidal pinch. 

This bit on IEC is pretty jumbled: im just writing it on a particularly
slow afternoon at work, as it comes to me.. ;)






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