Study of the Magneto-sonic Mach Number for the Magnetosphere of the Earth
Megha Agari *
Department of Physics, Soban Singh Jeena University, Almora, Uttarakhand, India.
L.P. Verma
Department of Physics, Soban Singh Jeena University, Almora, Uttarakhand, India.
*Author to whom correspondence should be addressed.
Abstract
The Magnetosonic Mach number is a non-dimensional parameter that calculates the velocity of the solar wind in relation to the velocity of magnetosonic waves within the same medium, which plays a crucial role in magnetospheric interactions. It influences the efficiency between planetary and interplanetary magnetic fields, affecting phenomena like the solar-wind magnetosphere interaction. The magnetosonic Mach number in correlation with the Disturbance Storm Time index, plays a crucial role in comprehending and forecasting the energy transfer dynamics occurring during magnetic storms. This study aims to investigate the variation of Magnetosonic Mach Number with disturbance storm time index (Dst-index) for the moderate and intense geomagnetic storms. The superposed epoch method and correlation analysis are used to find the variation between different parameters and the Dst-index. According to this study for the solar cycle 25, the Magnetosonic Mach number not strongly correlated with the Dst-index for solar cycle 25 shows a weak correlation such 0.3.
Keywords: Interplanetary magnetic field, magnetosphere, solar wind, geomagnetic storm