SM048-03
Evidence of Sub-proton-scale Magnetic Holes in the Venusian Magnetosheath

Tuesday, 15 December 2020: 16:08
Virtual
Katherine Goodrich1, John W Bonnell2, Shannon Curry3, Roberto Livi3, Phyllis L Whittlesey3, Forrest Mozer4, David Malaspina5, Stuart D Bale6, Trevor A Bowen1, Anthony W Case7, Thierry Dudok de Wit8, Keith Goetz9, Jasper S Halekas10, Peter Harvey11, Justin Christophe Kasper12, Davin E Larson13, Robert J. MacDowall14, Michael McManus6, Marc Pulupa3 and Michael Louis Stevens7, (1)University of California Berkeley, Berkeley, CA, United States, (2)University of California, Berkeley, Space Sciences Laboratory, Berkeley, CA, United States, (3)Space Sciences Laboratory, University of California Berkeley, Berkeley, CA, United States, (4)University of California, Berkeley, Berkeley, CA, United States, (5)University of Colorado, Astrophysical and Planetary Sciences Department, Boulder, CO, United States, (6)University of California Berkeley, Space Sciences Laboratory, Berkeley, CA, United States, (7)Smithsonian Astrophysical Observatory, Cambridge, MA, United States, (8)LPC2E, CNRS and University of Orléans, Orléans, France, (9)University of Minnesota, School of Physics and Astronomy, Minneapolis, MN, United States, (10)University of Iowa, Department of Physics and Astronomy, Iowa City, IA, United States, (11)Space Sciences Laboratory, Berkeley, United States, (12)University of Michigan, Climate and Space Sciences and Engineering, Ann Arbor, MI, United States, (13)Space Sciences Laboratory, Berkeley, CA, United States, (14)NASA Goddard SFC, Greenbelt, MD, United States
Recorded Presentation
Abstract:
We present the first evidence of sub-proton-scale magnetic holes in the Venusian magnetosheath. Depressions in magnetic field strength, commonly referred to as magnetic holes, are observed ubiquitously in space plasmas. Magnetic holes with spatial scales larger than the local proton gyroradius (ρ) are usually attributed to the mirror instability. Those smaller than or on the order of ρ, termed "sub-proton-scale" magnetic holes, are likely supported by electron currents vortices, rotating perpendicular to the ambient magnetic field. While there are numerous accounts of sub-proton-scale magnetic holes within the Earth's magnetosphere, there are no reported observations in other space plasma environments. 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 field associated with magnetic depressions are consistent with electron current vortices with amplitudes on the order of 1μA/m2. This observation suggests sub-proton-scale magnetic holes are signatures of a universal process in space plasmas.
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