Ghag, K;
Raghav, A;
Shaikh, Z;
Nicolaou, G;
Dhamane, O;
Shah, M;
Panchal, U;
... Kumbhar, K; + view all
(2024)
Distinct polytropic behavior of plasma during ICME-HSS interaction.
Advances in Space Research
10.1016/j.asr.2024.09.073.
(In press).
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Abstract
Interplanetary Coronal Mass Ejections (ICMEs) and High-Speed Streams (HSSs) are significant drivers of space disturbance in interplanetary space. The interaction between these structures can lead to various phenomena, including the generation of waves, enhanced geo-effectiveness, particle acceleration, and more. However, understanding the plasma thermodynamic properties during an ICME-HSS interaction remains an open problem. In this study, we utilize observations from STEREO and WIND to investigate the thermodynamic behavior of plasma within an ICME and a HSS. Here, we used the thermal pressure (Pth) and proton number density (Np) data from spacecraft. By fitting the linear model to the scattered data of lnPth vs lnNp we estimated the polytropic index (α). Our analysis reveals that the ICME observed before its interaction with the HSS by STEREO-A exhibits a polytropic index α∼1.0, indicating an isothermal process. Conversely, WIND observations of the same ICME before its interaction with the HSS show a nearly isothermal behavior, with α=0.7. The HSS observed by WIND demonstrates α=1.8 before its interaction with the ICME. Further analysis of WIND observations within the ICME-HSS interaction region determines a polytropic index of α=2.5. These findings suggest that the HSS region displays a nearly adiabatic behavior, the ICME region manifests closely isothermal characteristics, and the ICME-HSS interaction region exhibits super-adiabatic behavior. We propose that the expansion of ICME increases due to its propagation in the vicinity of HSS, potentially leading to additional cooling of the observed ICME magnetic cloud, which differs from the ambient solar wind.
| Type: | Article |
|---|---|
| Title: | Distinct polytropic behavior of plasma during ICME-HSS interaction |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.asr.2024.09.073 |
| Publisher version: | http://dx.doi.org/10.1016/j.asr.2024.09.073 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10200743 |
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