Examining the Turbulent Nature of The Solar Atmosphere

The Parker Solar Probe (PSP) entered the sub-Alfvénic solar wind region for the first time during its eighth encounter. Since then, PSP has been entered into the sub-Alfvénic region several times. This is a region where the PSP is in direct contact with the solar atmosphere. Turbulence is thought to be one of the promising mechanisms for heating the solar corona to millions of Kelvin and accelerating the solar wind from sub-sonic to super-sonic speeds. Therefore, it is of great significance to study the turbulent characteristics of the solar wind over the sub-Alfvénic region. Since the PSP provided us with several hours of the sub-Alfvénic solar wind (magnetometer and plasma) data, we take this opportunity to study the turbulence characteristics in the sub-Alfvénic solar wind. We will study the variation of the energy-containing range and the inertial range turbulence energy in the direction perpendicular and parallel to the mean magnetic field in the sub-Alfvénic region. Similarly, we will study the power spectral density of perpendicular and parallel turbulence components, in which we determine how the power-law exponent changes with increasing distance in the sub-Alfvénic solar wind. Our study will shed light on coronal heating and the acceleration of the solar wind.