Ignition condition in Tokamak experiments and role of neutral injection heating

Abstract

The condition for toroidal experiments to become energetically self-sustaining is examined and a simple relationship is given between the self-ignition temperature and the plasma current. The temperature is limited at low density by synchrotron radiation and at high density by βθ-limitations. Tokamaks could, in principle, reach ignition conditions on Ohmic heating alone but will probably be limited by synchrotron radiation. A quite modest additional heating source allows ignition at higher density and the consequent examination of βθ limitations. The power and energy requirements for neutral beam heating are examined and shown to be compatible with existing technology.

Feedback Control of Major Disruptions in Tokamaks

“…Then for T e ϳ 3.5 keV, s e 1 s i 1 s x ϳ 6 3 10 216 cm 2 [8]. For a typical g 0 ϳ 10 4 s 21 (ideal growth rate modified by conducting wall, diamagnetic and other effects), R ϳ 240 cm, a 0 ϳ 80 cm, N 0 ϳ 3 3 10 13 cm 23 , we find from Eq.…”

Magnetic Domain Structures in CoCr Films Studied by Lorentz Microscopy

“…The pertinent processes are for trapping: charge exchange process. Reaction [58] is known theoretically [68]. Reaction (6) is also known [69,70].…”

Intense, mixed-energy hydrogen beams for CTR injection

“…in the other neutral components (full-energy molecules and lower-energy atoms and molecules) is also shown. The neutral particle ·penetration thi~kness,·P._ T. (ions/cm 2 ), in a fusion-experiment plasma is a function of the particle energy, so the lower-energy neutra,ls will not penetrate as far as those at full energy; we have used penetration thicknesses given by Sweetman [ 5] to estimate a mean r'elative penetration thickness, (P. T ), for the lower-energy neutral components. .…”

“…The neutral components with less than full energy may -10-or may not be desirable in a given experiment, but we note two possible disadvantages: First, the lower-energy components may make experiments more difficult (for example, energy-equilibration time measurements). Second, since the neutral particle pene~ration thickness ' (ions/cm 2 ) is approximately proportional to the neutral particle energy for a given species [5], lower-energy neutrals will be trapped at larger radii, and may be lost r~pidly to walls (for example, by charge exchange) or limiters.…”