Evidence of Subproton‐Scale Magnetic Holes in the Venusian Magnetosheath
K. Goodrich, J. W. Bonnell, Shannon Curry, R. Livi, P. L. Whittlesey, F. S. Mozer, D. Malaspina, J. S. Halekas, Michael D. McManus, S. D. Bale, Trevor A. Bowen, A. W. Case, Thierry Dudok de Wit, K. Goetz, P. Harvey, J. C. Kasper, D. E. Larson, R. J. MacDowall, M. Pulupa, M. L. Stevens
Abstract
Abstract Depressions in magnetic field strength, commonly referred to as magnetic holes, are observed ubiquitously in space plasmas. Subproton‐scale magnetic holes with spatial scales smaller than or on the order of a proton gyroradius, are likely supported by electron current vortices, rotating perpendicular to the ambient magnetic field. While there are numerous accounts of subproton‐scale magnetic holes within the Earth’s magnetosphere, there are few, if any, reported observations in other space plasma environments. We present the first evidence of subproton‐scale magnetic holes in the Venusian magnetosheath. During Parker Solar Probe’s first Venus Gravity Assist, the spacecraft crossed the planet’s bow shock and subsequently observed the Venusian magnetosheath. The FIELDS instrument suite onboard the spacecraft achieved magnetic and electric field measurements of magnetic hole structures. The electric fields associated with magnetic depressions are consistent with electron current vortices with amplitudes on the order of 1 μ A/m 2 .