Λεπτομέρειες βιβλιογραφικής εγγραφής
| Τίτλος: |
Wave‐Based Quantification of Ion Composition in the Earth's Magnetosphere‐Ionosphere‐Coupling Region. |
| Συγγραφείς: |
Qin, Zhijie1,2 (AUTHOR), Zhu, Hui1,2 (AUTHOR) huizhu@email.sdu.edu.cn, Ouyang, Zhihai3,4 (AUTHOR) oy_zhihai@ncu.edu.cn, Chen, Huicong1,2 (AUTHOR), She, Zhenghao1,2 (AUTHOR) |
| Πηγή: |
Geophysical Research Letters. 4/16/2026, Vol. 53 Issue 7, p1-11. 11p. |
| Θεματικοί όροι: |
*Magnetosphere, *Ionosphere, *Plasma diagnostics, *Electromagnetic waves, *Magnetospheric physics, *Waves (Physics) |
| Περίληψη: |
Ion composition critically determines the basic kinetic characteristics of plasma and affects energy transmission of the magnetosphere. However, it exhibits significant variations with altitude, latitude, local time, longitude, and also with geomagnetic and solar activity. Equatorial noise (EN) emissions, a frequently observed electromagnetic wave in the inner magnetosphere, propagate across magnetic field lines, and thus can reach magnetosphere‐ionosphere‐coupling (MIC) region near the magnetic equator, where their evolution depends on local ion composition. Here we utilize polarization reversal of EN emissions observed near the perigees of Van Allen Probes to in turn derive the compositions of helium and oxygen ions and provide comprehensive ion composition distributions by statistical analysis of EN emissions. Comparisons with the International Reference Ionosphere model and in situ plasma measurements validate the reliability of the estimated results. These findings advance MIC plasma models, and our method provides an indirect tool for plasma diagnostics on other planets. Plain Language Summary: Plasma is crucial for understanding physical processes in the region where the Earth's upper atmosphere and magnetosphere interact. However, directly measuring ion composition in this region is very difficult. Our research introduces an approach to this problem by analyzing a special type of naturally generated electromagnetic wave known as Equatorial Noise. These waves are common in space near Earth's equator. As they propagate toward Earth, they pass through the region where direct measurement is challenging and undergo a process of polarization reversal (the wave's polarization changes from right‐handed to left‐handed). We find that the polarization reversal depends directly on the local ion composition. By analyzing the reversal process using data from the Van Allen Probes, we estimate the ion composition. Our results, validated against the International Reference Ionosphere model and in situ measurements, provide reliable estimates of ion composition. This method improves plasma models of near‐Earth space and can be used as a tool to diagnose plasma around other planets, without the need for direct plasma measurement. Key Points: An approach to infer ion composition based on the characteristic frequencies of equatorial noise polarization reversal is proposedThe ion composition distributions in the magnetosphere‐ionosphere‐coupling region based on Van Allen Probe observation are obtainedOur results provide new insights for plasma diagnostics on the Earth and other planets [ABSTRACT FROM AUTHOR] |
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