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Acceleration of Interstellar Pickup He + at Earth's Perpendicular Bow Shock
Author(s) -
Starkey M. J.,
Fuselier S. A.,
Desai M. I.,
Burch J. L.,
Gomez R. G.,
Mukherjee J.,
Russell C. T.,
Lai H.,
Schwartz S. J.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl084198
Subject(s) - bow shock (aerodynamics) , physics , heliosphere , shock (circulatory) , acceleration , plasma , upstream (networking) , pickup , computational physics , perpendicular , solar wind , shock wave , reflection (computer programming) , mechanics , nuclear physics , classical mechanics , geometry , medicine , computer network , image (mathematics) , mathematics , artificial intelligence , computer science , programming language
On 05 December 2015 the Magnetospheric MultiScale constellation observed interstellar pickup ion distributions during an inbound crossing of Earth's perpendicular bow shock near the subsolar point, which provides new insights into shock acceleration of pickup ions throughout the heliosphere. In this study we analyze the upstream and downstream velocity distributions of H + and He + using data from the Hot Plasma Composition Analyzer on Magnetospheric MultiScale. We derive average two‐dimensional pitch angle distributions in the upstream and downstream field‐aligned bulk plasma frame, as well as integrated one‐dimensional velocity distributions. By comparing the upstream and downstream distributions, we find evidence of accelerated H + and He + downstream of the shock. By comparing measured and theoretical reflection ratios for He + , we attribute a significant part of this acceleration to a single reflection at the shock.