arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 2212.04860physics.plasm-phphysics.comp-ph
收藏

磁场梯度和二次电子发射对ExB等离子体位形中不稳定性和输运的影响

Effects of magnetic field gradient and secondary electron emission on instabilities and transport in an ExB plasma configuration

Maryam Reza, Farbod Faraji, Aaron Knoll

AI总结:

本研究使用降阶PIC代码模拟霍尔推进器,探讨了磁场梯度、二次电子发射等因素对ExB等离子体不稳定性和输运的影响,发现高密度下逆能量级联形成高频方位角模式,强磁场梯度会加剧电子交叉场输运和离子加热。

摘要:

如今,部分磁化的低温等离子体(LTP)在ExB位形中(即外加磁场垂直于自洽电场)具有重要的工业应用。霍尔推进器作为一种静电等离子体推进技术,是主要的LTP技术之一,其发展受到尚未完全明确的底层运行物理机制的阻碍,尤其是在等离子体不稳定性及相关的电子交叉场输运方面。具有非常规磁场拓扑的霍尔推进器的发展,进一步提出了关于这些现代交叉场位形中不稳定性特征和电子动力学的问题。因此,在本研究中,我们针对霍尔推进器径向-方位角坐标下的等离子体过程,开展了一系列关于四个因素影响的研究,即磁场梯度、二次电子发射、电子-中性粒子碰撞和等离子体数密度。这些研究使用作者开发的降阶粒子模拟(PIC)代码进行。径向-方位角模拟的设置在很大程度上遵循了文献中一个明确的基准案例,其中磁场沿半径方向取向,并施加垂直于模拟平面的恒定轴向电场。我们研究的重要发现是,在对应于较高等离子体密度的研究案例中,逆能量级联导致了一个长波长、高频方位角模式的形成。此外,在存在强磁场梯度的情况下,该模式得到充分发展,并引起了显著的电子交叉场输运以及离子群的明显加热。

英文摘要:

Today, partially magnetized low-temperature plasmas (LTP) in an ExB configuration, where the applied magnetic field is perpendicular to the self-consistent electric field, have important industrial applications. Hall thrusters, a type of electrostatic plasma propulsion, are one of the main LTP technologies whose advancement is hindered by the not-fully-understood underlying physics of operation, particularly, with respect to the plasma instabilities and the associated electron cross-field transport. The development of Hall thrusters with unconventional magnetic field topologies has imposed further questions regarding the instabilities' characteristics and the electrons' dynamics in these modern cross-field configurations. Accordingly, we present in this effort a series of studies on the influence of four factors on the plasma processes in the radial-azimuthal coordinates of a Hall thruster, namely, the magnetic field gradient, Secondary Electron Emission, electron-neutral collisions, and plasma number density. The studies are carried out using the reduced-order particle-in-cell (PIC) code developed by the authors. The setup of the radial-azimuthal simulations largely follows a well-defined benchmark case from the literature in which the magnetic field is oriented along the radius and a constant axial electric field is applied perpendicular to the simulation plane. The salient finding from our investigations is that, in the studied cases corresponding to elevated plasma densities, an inverse energy cascade leads to the formation of a long-wavelength, high-frequency azimuthal mode. Moreover, in the presence of strong magnetic field gradients, this mode is fully developed and induces a significant electron cross-field transport as well as a notable heating of the ion population.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑