``Runaway'' Electrons and Cooperative Phenomena in B-1 Stellarator Discharges
``Runaway'' Electrons and Cooperative Phenomena in B-1 Stellarator Discharges
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DOI：
10.1063/1.1724360
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发表时间：
1958-09
影响因子：
4.6
通讯作者：
W. Bernstein;Francis F. Chen;M. A. Heald;A. Kranz
中科院分区：
文献类型：
--
作者：
W. Bernstein;Francis F. Chen;M. A. Heald;A. Kranz
对B - 1恒星在脉冲放电过程中发出的30 kev以上x射线的时间分布、相对强度和最大能量的研究揭示了许多有趣的现象。x射线被认为是由“失控”的电子撞击壁时产生的。已经观察到虚假的大脉冲高度。x射线在放电早期突然出现，在克鲁斯卡尔不稳定发生之前。根据操作条件的不同，在放电过程中的任何时候都可以观察到x射线，除非电流处于克鲁斯卡尔极限值。如果用于欧姆加热的纵向电场是“crowbar”的，则随后会出现大量的x射线；此外，放电电流会随x射线的爆发而突然衰减。假设这些步骤中的电流完全是由失控的电子引起的，这与数据是一致的。这些观察结果被认为是存在协同现象或集体运动的证据，这些现象或集体运动可以影响等离子体的约束和加热。此外，强烈的非热微波噪声在与x射线发射相关的时间被检测到。
Examination of the temporal distribution, relative intensity, and maximum energy of x‐rays above 30 kev emanating from the B‐1 stellarator during a pulsed discharge has revealed a number of interesting phenomena. The x‐rays are assumed to be produced by ``runaway'' electrons when they strike the wall. Spuriously large pulse heights have been observed. The x‐rays abruptly appear early in the discharge, before the Kruskal instability can occur. Depending on the operating conditions, x‐rays can be observed at any time during the discharge except when the current is at the Kruskal limiting value. If the longitudinal electric field used for ohmic heating is ``crowbarred,'' x‐rays can appear afterwards in copious quantities; furthermore, the discharge current can decay in abrupt steps correlated in time with bursts of x‐rays. The hypothesis that the current in these steps is due entirely to runaway electrons is consistent with the data. These observations are taken to be evidence for the existence of cooperative phenomena, or collective motions which can affect both the confinement and the heating of a plasma. In addition, intense nonthermal microwave noise has been detected at times correlated with x‐ray emission.