Numerical simulations of a sounding rocket in ionospheric plasma: Effects of magnetic field on the wake formation and rocket potential

Abstract

The charging of a sounding rocket in subsonic and supersonic plasma flows with external magnetic field is studied with numerical particle‐in‐cell (PIC) simulations. A weakly magnetized plasma regime is considered that corresponds to the ionospheric F2 layer, with electrons being strongly magnetized, while the magnetization of ions is weak. It is demonstrated that the magnetic field orientation influences the floating potential of the rocket and that with increasing angle between the rocket axis and the magnetic field direction the rocket potential becomes less negative. External magnetic field gives rise to asymmetric wake downstream of the rocket. The simulated wake in the potential and density may extend as far as 30 electron Debye lengths; thus, it is important to account for these plasma perturbations when analyzing in situ measurements. A qualitative agreement between simulation results and the actual measurements with a sounding rocket is also shown.

Electron Wing‐Like Structures Formed at a Negatively Charged Spacecraft Moving in a Magnetized Plasma

“…The negative potential area is further extended downstream due to the absence of positive ions behind the spacecraft. Such electrostatic features are typical for solid obstacles placed in supersonic plasma flows even with static magnetic fields (Darian et al, ; Usui et al, ).…”

“…With the change in dominant ion species, the spacecraft can be supersonic at low altitudes, and subsonic at high altitudes. In both cases, a wake will form downstream of the spacecraft, which for supersonic flows can extend much farther than the Debye length from the spacecraft surface (Al'pert et al, 1966;Khrapak et al, 2005;Ludwig et al, 2012;Miloch, 2014;Darian et al, 2017;Paulsson et al, 2019).…”

“…The importance of the sheath and wake effects for in-situ measurements has been recognized early, and a number of studies were carried out to address this problem with increasingly more realistic models and simulations (Wang & Hastings, 1992;Scime et al, 1994;Torkar et al, 1998;Engwall et al, 2006;Svenes & Trøim, 1994;Garrett & Whittlesey, 2000;Anderson, 2012;Marchand et al, 2014;Miyake & Usui, 2016;Marchand & Lira, 2017;Capon et al, 2017). Due to the computational complexity, only recently, the effects of the magnetic field on the wake and spacecraft charging have been studied in self-consistent simulations (Marchand, 2012;Darian et al, 2017). In a magnetized plasma, which is found at LEO, the electron dynamics are controlled by the magnetic field, and thus, the wake can be modified as compared to the unmagnetized case, and also become asymmetric (Darian et al, 2017;Usui et al, 2019).…”

“…Due to the computational complexity, only recently, the effects of the magnetic field on the wake and spacecraft charging have been studied in self-consistent simulations (Marchand, 2012;Darian et al, 2017). In a magnetized plasma, which is found at LEO, the electron dynamics are controlled by the magnetic field, and thus, the wake can be modified as compared to the unmagnetized case, and also become asymmetric (Darian et al, 2017;Usui et al, 2019). Note that an object in flowing plasmas is still one of outstanding problems of general interest in plasma physics, including complex plasmas, charging of solar system small bodies, or probe measurement techniques (Shukla & Mamun, 2002;Vladimirov et al, 2005;Holmström et al, 2012;Miyake & Nishino, 2015;Beadles et al, 2017;Darian et al, 2019).…”

Dynamic ion shadows behind finite-sized objects in collisionless magnetized plasma flows

“…However, in the view of recent dusty plasma experiments with external magnetic fields [25][26][27], and also in the general context of object-plasma interactions, it is of high urgency to understand the microphysics of wake formation in magnetized plasmas. A few such attempts have been done recently with PIC simulations for E B ´ drifting plasmas, where E  and B  are, respectively, the electric and magnetic field [28,29], as well as with the LR approach for a magnetic field aligned with the flow direction [30][31][32][33][34]. The latter configuration is relevant for recent experiments with dust particle pairs in magnetic fields [25].…”