The energy balance of an arc discharge in hydrogen gas

The temperature profile in a thermonuclear reactor

“…The solution of this equation f ie 4e 2 B 2 V, 1 "do T o kT* e . (14) shows n d to be a positive (-V dr is positive) and monotonically increasing function of r. Similarly, Eqs (1) and ( 5) for the helium density yield…”

“…From arc physics we know that the energy necessary to heat and ionize the atoms transported by ambipolar diffusion is much larger than the energy transported by ordinary heat conduction [14] so V dr is much smaller than the ambipolar diffusion velocity, as was assumed above. What is said above is certainly not true near the boundary formed by Q P = Q R because then Qcond "* 0' a^d there is not enough energy left for Qconv But this occurs only very close to this boundary.…”

Density limit of tokamaks

“…Here the toroidal plasma current density drops to a low level, and the contribution from the pinch effect becomes small compared with that from the ionization rate. Also the contribution from the Nernst effect is found to be negligible within these layers [29][30][31].…”

The dependence of pressure on the magnetic field in an arc surrounded by cold gas

“…The inhibiting effect of a strong axial magnetic field on the heat loss from an arc to a surrounding cold gas is well-known. It can be attributed to the dependence of the thermal conductivity, whose main contribution comes from the ions (the temperature inside the arc is so high that almost no neutrals are present and C^T^ » 1) 2n t kT (1) on the magnetic field strength B; gfs. is the thermal conductivity of ions, ui the cyclotron frequency of ions, Ti the ion collision time, n t the ion density, mi the ion mass, k the Boltzmann constant and T the temperature.…”

“…To be able to proceed we shall have to make simplifying assumptions in many places. Although not always stated explicitly,all of these can be shown to be justified by making use of the computer data [1] .…”