ORIGINAL RESEARCH article
Front. Astron. Space Sci.
Sec. Space Physics
This article is part of the Research TopicKinetic-Scale Processes and Small-Scale Structures Embedded within Large-Scale Solar Wind StructuresView all articles
Role of Kinetic Alfv´en Waves in the Non-Extensive Anisotropic Earth's Magnetospheric Plasma
Provisionally accepted
- 1Department of Space Science, Institute of Space Technology, Islamabad 44000, Pakistan, Islamabad, Pakistan
- 2Space and Astrophysics Research Lab (SARL), National Center of GIS and Space Applications (NCGSA), Islamabad 44000, Pakistan, Islamabad, Pakistan
- 3Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, United States
- 4The University of Alabama in Huntsville, Huntsville, United States
- 5Department of Physics, Faculty of Science, Mahidol University, Bangkok 10400, Thailand, Salaya, Thailand
- 6National University of Science Technology (NUST), Sector H-12, Islamabad, Pakistan, Islamabad, Pakistan
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Kinetic Alfv´en waves (KAWs) contribute significantly to particle acceleration in the magnetosphere of Earth. In this paper, we discussed how the charged particles' (electrons and ions) speeds vary with distance during the wave-particle interaction. We employed the temperature-anisotropic non-extensive distribution function to model the magnetospheric plasma. Our findings show that the charged particles take more energy from the wave in the non-extensive state; consequently, the particles are accelerated to higher velocities. Our results also show that when the perpendicular ion temperature (T⊥i) of the system increases, the accelerated charges have a lower velocity. In addition to the velocity of charged particles, we found that the magnitude of the KAW's group velocity was larger in the Maxwellian (q →1) case, and the waves were more energetic and heat the magnetospheric plasma for larger distances. Finally, we calculated the characteristic length scale over which the waves get damped. Our findings show that the damping scale length is of the order of several Earth radii (RE), consistent with observations. The effects of q and the temperature anisotropy on the damping scale length are such that for small q (i.e., the non-extensive state), and larger T⊥i, the damping scale length becomes large enough, which implies that the waves can interact with the charged particles far away from the locations where they are excited. The findings of this study help us understand the formation of the beams of charged particles, which can precipitate into different regions of the magnetosphere, and are critically important in the formation of auroras.
Keywords: Damping Length, Group velocity, kinetic Alfv´en waves, Magnetospheric plasma, Poynting vector, temperature anisotropic non-extensive distribution function
Received: 20 Nov 2025; Accepted: 26 Jan 2026.
Copyright: © 2026 Ali Khan, Ayaz, Shamir and Khokhar. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Syed Ayaz
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