MAVEN Survey of Magnetic Flux Rope Properties in the Martian Ionosphere:
Comparison with 3 Types of Formation Mechanisms
Abstract
Flux ropes are a magnetic field phenomenon characterized by a filament
of twisted magnetic field with an axial core and outer helical wraps.
They form in the Martian ionosphere via three distinct mechanisms:
boundary wave instabilities (BWI), external reconnection (ER) between
the interplanetary magnetic field and the crustal anomalies, and
internal reconnection (IR) of the crustal anomalies themselves. We have
identified 121 magnetic flux ropes from 1900 orbits using plasma and
magnetic field measurements measured by the Mars Atmosphere and Volatile
EvolutioN (MAVEN) spacecraft, and separate flux ropes into categories
based on formation mechanism by analyzing electron signatures. We find
evidence for flux ropes formed via BWI, ER, and IR mechanisms which
comprise 9%, 34%, and 57% of our dataset, respectively. Flux ropes
formed via different mechanisms exhibit differences in location and
force-free radius, indicating the formation mechanism of a flux rope
impacts their influence on the Martian plasma environment.