Interaction of Space Weather Phenomena With Mars Plasma Environment During Solar Minimum 23/24

TL;DR

This study analyzes how solar wind structures during solar minimum 23/24 affected Mars' plasma environment, revealing significant variations in bow shock location, magnetospheric compression, and plasma flow despite low solar activity.

Contribution

It provides the first detailed analysis of Mars' plasma response to specific solar wind structures during a solar minimum period.

Findings

Bow shock location varied between 2.2 and 3.0 R_M.

Magnetospheric cavity compressed up to 45%.

Transterminator flow increased by up to 8 times.

Abstract

We study the interaction of three solar wind structures, two stream interaction regions and one interplanetary coronal mass ejection, with Mars' plasma environment during 20-27 November 2007. This period corresponds to the solar minimum between the solar cycles 23 and 24 which was characterized by very low values of the solar wind density and dynamic pressure and low IMF magnitude. During that time the Mars-Express orbit was in the terminator plane, while the Earth, Sun, and Mars were almost aligned, so we use the ACE and STEREO probes as solar wind monitors in order to identify and characterize the structures that later hit Mars. We find that the passage of these structures caused strong variations of in the bow shock location (between 2.2 and 3.0~R$_M$), compression of the magnetospheric cavity (up to 45~\%) and an increased transterminator flow below 2~R$_M$ (by a factor of $\leq$8). This study shows that during times of low solar activity, modest space weather phenomena may cause large variations of plasma flow at Mars.