High-power electron-beam transport in long gas cells from 10(sup (minus)3) to 10(sup 3) Torr nitrogen

摘要

Measurements and analyses show that the 13-TW, pulsed Hermes-III electron beam, with current near the Alfven limit, has two regimes of stable transport: a low-pressure window (between (approximately) 1 and (approximately) 100 mTorr) that is dominated by propagation in the semi-collisionless IFR (ion-focused regime), and a high-pressure window (between (approximately) 1 and (approximately) 100 Torr) that is dominated by propagation in the resistive CDR (collision-dominated regime). Below (approximately) 1 mTorr, there is insufficient ionization to confine the beam; between the windows, the two-stream and hollowing instabilities disrupt propagation; and above (approximately) 100 Torr, the resistive hose instability degrades propagation.