Dynamics of a positive probe in ExB drifting plasma: 3-D electromagnetic particle-in-cell simulations

Summary form only given. We present the recent results of a series of electromagnetic particle-in-cell simulations, taken over a broad range of parameter space, that modeled a positive probe in E×B drifting plasma. These results address two fundamental problems: momentum coupling in magnetized flowing plasma and the plasma/sheath dynamics of a positive probe in E×B drifting plasma. In these simulations we observed rarefied electron wings develop along the magnetic field in the wake of the positive probe and a quasi-trapped electron region. Depending on the parameter regime, either electrostatic or electromagnetic waves formed in the probe´s wake (directly downstream of the probe or along the rarefied electron wings), similar to predictions by Stenzel and Urrutia¹. Additionally, we report on sheath dynamics of a positive probe in E×B drifting plasma, which were clearly resolved and indicated multiple electron heating processes. These electron heating processes included electron heating due to the quasi-trapped electron mode as well as electron heating due to wave-particle interactions in the ram region of the probe and along the electron rarefied wings. These electron heating processes significantly affect the overall current collected by the probe².