Work

Suprathermal Outflowing H + Ions in the Lobe Driven by an Interplanetary Shock: 1. An Observation Event

Year: 2024

Type: article

Abstract: To better understand how sharp changes in the solar wind and interplanetary magnetic field conditions affect the ionosphere outflows at high latitudes, we analyze an event observed on 17 July 2002 showing suprathermal (tens to hundreds of eV) outflowing H + ions in the lobe driven by the impact of an interplanetary (IP) shock. A spacecraft in the lobe at altitudes of ∼6.5 R E first observed enhanced downward DC Poynting fluxes ∼2 min after the shock impact and then, another 8 min later, the appearance of suprathermal outflowing H + ions as ion beams and ion conics. The increasing downward DC Poynting fluxes and the increasing outflowing H + fluxes that appeared later were highly correlated because they shared a similar increasing trend with a time scale of ∼5 min. To explain such time delay and correlation, we conclude that a plausible scenario was that the enhanced DC Poynting fluxes reached down to lower altitudes, drove processes to accelerate the pre‐existing polar wind ions to ion beams and ion conics, and then these newly generated suprathermal ions flowed upward to the spacecraft altitudes. This event indicates that an IP shock can drive a significant amount of suprathermal H + outflows from the polar cap.

Source: Journal of Geophysical Research Space Physics

DOI: 10.1029/2024ja032557

Authors: Chih‐Ping Wang, C. G. Mouikis, Xueyi Wang, Arnaud Masson, Yu Lin

Institutions: University of California, Los Angeles, University of New Hampshire, Auburn University, European Space Agency, European Space Astronomy Centre

Language: English

Topic: Ionosphere and magnetosphere dynamics

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,880

Funders: National Science Foundation, National Aeronautics and Space Administration, Nuclear Safety and Security Commission, Goddard Space Flight Center