nouveau bandeau du PNST 2022

Investigation of solar wind kinetic properties and velocity distribution function during Parker Solar Probe and Solar Orbiter radial alignments
Rungployphan Kieokaew  1@  
1 : Institut de recherche en astrophysique et planétologie
Institut National des Sciences de l'Univers : UMR5277, Université Toulouse III - Paul Sabatier, Observatoire Midi-Pyrénées, Centre National de la Recherche Scientifique : UMR5277, Institut National des Sciences de l'Univers, Centre National de la Recherche Scientifique

The new space missions recently launched to the Sun – Parker Solar Probe (PSP) and Solar Orbiter (SO) – prompt us to a new era of solar wind studies. Particularly, there are several opportunities where PSP and SO align in the radial direction, allowing us to study the evolution of solar wind properties and structures as a function of distance from the Sun. I investigate the plasma properties of the solar wind major ions during PSP-SO radial alignments. Using a measure for global dependence of two time series, I identified plasma parcels that are plausibly intercepted by both spacecraft. By considering the kinetic properties of the ion observations at PSP and SO, it is found that the ion temperature anisotropy decreases while the ion beta increases away from the Sun. Using the linear instability analysis, it is found that a larger proportion of the data points are unstable to the proton cyclotron instability closer to the Sun. Moreover, the ion distributions in the velocity space, or the ion velocity distribution function (VDF), at PSP and SO for the same plasma parcel show different kinetic (non-Maxwellian) features. Using linear and quasi-linear instability analyses, I will discuss ion-kinetic activities and possible wave-particle interactions observed at PSP and SO with a focus on their effects on the production of non-Maxwellian features of VDF and the local energy transfer. This work contributes to the understanding of the solar wind ion energization, and the production of non-Maxwellian ion VDF features that in turn provide sources of free energy in the driving of the solar wind heating and acceleration.

 


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