Reply To: Military Effects

[Joseph Chikva]

Injectors
For electron injection it is more suitable to use Induction Linear Accelerators (Induction Linacs) producing:
• currents of kilo-amperes orders (10000 A by ATA accelerator [7])
• particles energies up to 50 MeV (with the spread <1% [7])
• pulse duration – 50 ns -1.2 μs
These parameters allow the effective injection of electron beams into the chamber with reasonable radial dimension (up to 2 m for modern TOKAMAKs)

For ions – the Ion Diodes or combination of Ion Diodes with additional Inductive Voltage Adders would be more suitable.
As:
• Ion Diodes produce currents up to mega-Amperes orders
• Energies of particles – up to several MeV (several hundreds keV are more common)
• Pulse duration – 50 ns – several μs
But energy spread produced by Ion Diodes is rather high and, so, big phase space.
From the one side wide spread would be useful for avoiding of some types of instabilities (e.g. two-stream instability) but from another – it makes more difficulties for injections. But as has been showed above, if electron beam would be injected before ions, that creates enough potential well for further injection of ions. Combination of Ion Diodes with Inductive Voltage Adders also dramatically reduces spread.

To apply the axial (toroidal) accelerating electric field.
If considering elastic collision of two particles moving at the same direction with different velocities, faster moving particle will transfer some momentum (and corresponding energy) to slower one, thus accelerating that and decelerating itself.
For the case when slower particle has bigger mass [1], [4]:

ΔE=γ2β2mc2 Θ/2
(3)
Δp= ΔE/v,

Where:
γ – relativistic factor of faster particle in the frame connected with slower
β – vrelative/c (vrelative – relative velocity of two particles)
m – mass of faster particle
Θ – scattering angle

And for interesting for us case average energy loss of faster moving Deuteron per each elastic collision (scattering event):

ΔE=10.9eV (corresponds to Θ=0.85 deg)
And taking into account that ratio between scattering and fusion cross sections differs on about 4 orders of magnitude, we should wait that:
• Deuteron 450keV decelerates to ~340keV
• Triton 300keV accelerates to ~410keV
before they fuse.
Naturally, mentioned above kinetic energies do not provide collision energy sufficient for fusion (not less than 10keV in center-of-mass frame)

And for this reason it is offered to apply along the axis the electric field accelerating particles in a manner similar to TOKAMAK in which that firstly breakdowns gas, ionizing that and drives the current.

TOKAMAK needs comparatively high intensity of electric field initially (up to 100 V/m when gas breakdown goes) but then by growth of plasma conductivity required intensity should be much lower (typical value of loop voltage – from fraction of Volt to 1 Volt which corresponds to 0.5V/m of intensity and even lower). Nevertheless due to high conductivity of hot plasma this voltage drives mega-Amperes order current.

For estimation of required intensity of electric field let us admit that:
• number density of pinched combined beam – 1023 m-3
• required confinement time in this case – 10-3 sec
And in this time the electric field of 50 V/m intensity will give to deuterium additional energy ~387keV and to tritium – ~240keV

And as result after the lapse of offered cycle will have:
• Deuteron 450keV accelerates to ~727keV
• Triton 300keV accelerates to ~650keV
that provides collision energy in center-of-mass frame

21.6keV (quite sufficient for fusion)

Here we should also to notice that particles from the beginning having equal gyroradiuses as result of described phenomena gain the certain mismatch from equilibrium momentums (about 18%) but also we have described that attraction of three unidirectional currents creates enough potential well confining them together.
According data provided by Stallatron (high current Betatron with additional Stellarator type windings) developers [5] such a scheme allows mismatch of energies up to 50% from equilibrium.

Requirements on axial electric field
For creation of axial electric field if we would use iron core transformer made of permendur (saturation limit 2.5 T), circumference of toroidal chamber L=15 m, inner area available for core S=20 m2 , mentioned above electric field E=50 V/m intensity can be kept in:
Bmin= – 2.4 T
Bmax= 2.4 T
Loop voltage :
Vloop=LE

t= S(Bmax-Bmin)/LE=0.128 sec = 128 milliseconds

So, after 1 millisecond there is enough reserve to pass then on lower intensity (~0.5 V/m) using in TOKAMAK mode with hot plasma.
At once after injection from the walls with the help of corresponding valves to puff into the vacuum chamber the gas consisting the fusion fuel components until filling the chamber up to desired pressure.
It is offered to use several gas-puff valves divided along circumference of reactor in regular intervals and to open them at certain moment puffing the certain quantity of gas: e.g. equal (by volume) mix of deuterium and tritium gases.
Already being there halo-layer will ionize that gas and then generate the current similarly to that how current is generated in so called Advanced TOKAMAKs (H-mode – beam driven current) and rise the temperature until thermonuclear temperature (higher than 10keV)
As the energy of halo-layer is in more convenient for energy transfer form – fast moving ions, energy of those ions 3.5MeV + energy corresponding to velocity of center-of-mass frame (2.63*106 m/s in considering here case) and that energy will be absorbed by cold gas within a few milliseconds increasing its temperature to desired value (10 keV and higher)