Magnetohydrodynamical Understanding of the Interactions Between Coronal
Mass Ejections and Earth's Magnetosphere.
Coronal mass ejections (CMEs), the large scale transient eruptions from
the Sun, interact with the Earth’s magnetosphere while travelling into
the heliosphere. The energetic interplanetary CME (ICME) at 1AU not only
creates geomagnetic storms and disrupts the magnetic field structure
around the Earth but also impacts the plasma environment, causes strong
aurorae, and disturbs the radio and electrical transmission massively.
We use 3D compressible magnetohydrodynamic simulation of a star-planet
system and study the interesting magnetohydrodynamic processes like
bow-shock, magnetopause, magnetotail, planet-bound current sheets,
magnetic reconnections, atmospheric mass loss as well as particle
injection, etc., when an ICME flux rope crosses the Earth at 1 AU. We
use the uniformly twisted force-free flux rope model proposed by Gold
and Hoyle in 1960 to initiate the ICME and vary the flux rope properties
using actual observational data. We observe a change in magnetopause’s
shape and the stand-off distance to the magnetopause. We notice twist
helicity injection inside the magnetotail current system. We discover
comparative increment in both the rates of atmospheric mass out-flow and
solar wind in-flow in the vicinity of Earth during the geo-storm. Such
studies will help us understand how energetic magnetic storms from a
host star impact planetary magnetospheres and atmospheres with
implications for planetary and exoplanetary habitability.