Super-Adiabatic Cooling of Small Scale Magnetic Flux-Ropes in Inner Heliosphere: PSP Observation

Abstract

Small scale magnetic flux-rope (SSMFR) is ubiquitous in space plasma and contributes to several plasma processes such as; plasma transport, wave activity, acceleration, etc. Here, we have investigated the thermodynamics of three SSMFRs close to the Sun. The polytropic indices for all three SMFRs were greater than two, suggesting that the plasma shows super-adiabatic properties. Additionally, the SSMFRs' work-to-heat-supply ratios are greater than -0.6. It shows that more than 60% of the heat delivered to the system is used to carry out work, while the remaining is used to boost internal energy. Thus, the discovered super-adiabatic process would be critical in understanding the energy transfer from the SSMFR to the surrounding plasma.