Experimental study of a mini-magnetosphere

Abstract

Magnetosphere at ion kinetic scales, or mini-magnetosphere, possesses unusual features as predicted by numerical simulations. However, there are practically no data on the subject from space observations and the data which are available are far too incomplete. In the present work we describe results of laboratory experiment on interaction of plasma flow with magnetic dipole with parameters such that ion inertial length is smaller than a size of observed magnetosphere. A detailed structure of non-coplanar or out-of-plane component of magnetic field has been obtained in meridian plane. Independence of this component on dipole moment reversal, as was reported in previous work, has been verified. In the tail distinct lobes and central current sheet have been observed. It was found that lobe regions adjacent to boundary layer are dominated by non-coplanar component of magnetic field. Tail-ward oriented electric current in plasma associated with that component appears to be equal to ion current in the upstream part of magnetosphere and in the tail current sheet implying that electrons are stationary in those regions while ions flow by. Obtained data strongly support the proposed model of mini-magnetosphere based on two-fluid effects as described by the Hall term.

Reiner Gamma albedo features reproduced by modeling solar wind standoff

“…The two regions of strongest magnetic field are co-located with the brightest albedo markings. As the solar wind interaction with magnetic dipoles has been well studied [17][18][19][20][21][22][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] , it allows us better insight to confidently disentangle the plasma interaction with Reiner Gamma's magnetic topology. The high proton density profile surrounding the density cavities ( Fig.…”

On vertical electric fields at lunar magnetic anomalies

“…For example, Wang et al [2012Wang et al [ , 2013 identified potential structures related to the surface charging in a laboratory study using a magnetic dipole and a plasma flow with unmagnetized protons and magnetized electrons. Shaikhislamov et al [2013Shaikhislamov et al [ , 2014 studied laboratory measurements and a Hall-MHD simulation arguing that the Hall term of the electric field may play an important role in decoupling the ion and electron flow in lunar minimagnetospheres. Self-consistent fluid simulations predict the formation of lunar minimagnetospheres around the strongest lunar magnetic anomalies [e.g., Harnett and Winglee, 2000].…”

Three‐dimensional full‐kinetic simulation of the solar wind interaction with a vertical dipolar lunar magnetic anomaly

“…Over the last decade, the evolution from magnetohydrodynamic [ Harnett and Winglee , ; Shaikhislamov et al , , ; Xie et al , ] and hybrid [ Kallio et al , ; Jarvinen et al , ; Fatemi et al , ] toward full‐kinetic simulations [ Deca et al , , ; Ashida et al , ] has made it abundantly clear that the solar wind‐LMA interaction is highly nonadiabatic. The ability to investigate finite gyroradius effects and charge separation is therefore an absolute must to correctly describe the electron physics‐dominated LMA environment.…”