Discharge characteristics and increased electron current during azimuthally nonuniform propellant supply in an anode layer Hall thruster
Discharge characteristics and increased electron current during azimuthally nonuniform propellant supply in an anode layer Hall thruster
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DOI：
10.1063/1.5144851
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发表时间：
2020-07
影响因子：
3.2
通讯作者：
J. Bak;B. van Loo;R. Kawashima;K. Komurasaki
中科院分区：
文献类型：
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作者：
J. Bak;B. van Loo;R. Kawashima;K. Komurasaki
放电电流分量，如电子，离子束，和损失到壁电流，得到的霍尔推力器的方位角推进剂的不均匀性的函数。根据放电电流振荡和径向-方位角放电照相，讨论了放电特性。一个高度振荡的操作制度被发现伴随着有限的电子电流下的放电径向扩大的扩张。中性不均匀性的进一步增加导致静态放电与增强的电子电流和方位角分离的电离区域相结合。一个轴向的一维经典电子流的观点被发现来解释所观察到的电子电流的演变，直到适度的推进剂不均匀性发生。通过放电图像分析，表明等离子体的不均匀性线性增加相对于输入中性粒子的不均匀性。的不均匀性的演变并没有捕获在放电模式的变化过程中的电子电流的逐步增加，然而，在每个放电制度的单调增加的特点表明，等离子体性能的方位角梯度可以有助于增加电子电流。最后，削弱磁势垒的电子流导致轴向方位角的变化等离子体结构的另一个可能的原因，在非均匀推进剂操作中的电子电流增加。
Discharge current components, such as electron, ion beam, and lost-to-wall currents, are obtained as functions of azimuthal propellant inhomogeneity in a Hall thruster. Discharge characteristics are discussed based on discharge current oscillation and radial–azimuthal discharge photography. A highly oscillative operation regime is found to be accompanied by radially enlarged expansion of discharge under limited electron currents. Further increases in neutral inhomogeneity lead to quiescent discharge combined with enhanced electron currents and an azimuthally separated ionization region. An axial one-dimensional classical view of electron flow is found to explain the observed electron current evolution only until moderate propellant inhomogeneity occurs. Through discharge image analysis, it is shown that plasma inhomogeneity increases linearly with respect to the input neutral particle inhomogeneity. The evolution of the inhomogeneity does not capture a stepwise increase in the electron current during discharge mode changes; however, the monotonic increase featured in each discharge regime shows that the azimuthal gradient of plasma properties can contribute to increased electron current. Lastly, the weakened magnetic barrier to electron flow resulting from axial–azimuthal variation in plasma structures is presented as another possible cause of increased electron current in nonuniform propellant operations.