报告题目：Azimuthal instabilities and structures in penning discharges
报告人：Andrei Smolyakov
报告时间：2026年5月26日星期二9:30 –11:30
报告地点：物理科技楼155室
报告摘要：Penning (reflex) discharges are cross-field devices used in applications such as ion sources and as testbeds for plasma instability studies. Many operate with a negative central potential, producing an inward electric field that favors ion confinement but can drive the Simon‑Hoh instability, often linked to observed fluctuations. Regimes with an outward electric field, where the SH instability is suppressed, are also of interest, though other drift‑dissipative instabilities may arise.
2D3V PIC/MCC simulations show two steady‑state regimes: a large‑scale m=1 spoke mode and multiple small‑scale m>1 spiral arms. Transition from spiral arms to the spoke occurs when the central potential shifts from weakly positive/zero to negative, or with increased magnetic field. Full 3D3V simulations for a positive central potential reveal azimuthally rotating structures that are weakly correlated with axial fluctuations, rotating as a whole without axial shear. The spatial/temporal scales of these structures are characterized, and underlying instability mechanisms are discussed.
报告人简介：Andrei Smolyakov is a Professor in the Department of Physics and Engineering Physics at the University of Saskatchewan, Canada. His research interests include basic plasma physics with applications to magnetic fusion, laboratory plasmas, and plasma for electric propulsion. He is a Fellow of American Physical Society, a member of the editorial boards for several plasma physics journals and serves as an Associate Editor for Physics of Plasmas.
