Quasi‐Homologous Solar Flares and Impacts on Thermospheric Density and Satellite Orbital Drag

IF 5 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geophysical Research Letters Pub Date : 2026-10-14 DOI:10.1029/2026gl125768

S. Tulasi Ram,Princy K. Dubey,S. Mondal,Denny M. Oliveira,Jayashree Bulusu,Chinmaya Nayak,D. Rout,Anil Raghav,A. P. Dimri

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Abstract

Abstract Quasi‐Homologous Flaring (QHF) activity from active regions on the Sun releases intense electromagnetic radiation in recurrent bursts over extended periods. In this letter, we present the effects of recurrent impulsive extreme ultraviolet (EUV) heating on thermospheric neutral density and the resulting atmospheric drag on satellites based on Swarm‐A measurements. Significant density enhancements up to 25%–30% and 50%–75% sustained for a few days, on both day and night sides, were observed at ∼460 km altitudes during QHF from AR4366 (February 2026) and AR3664 (May 2024), respectively. As a result, Swarm‐A orbital decay rate is increased from 79.43 to 96.28 m/day, and from 19.91 to 42.43 m/day during the AR4366 and AR3664 QHF events, respectively. Repeated EUV heating at intervals shorter than the typical thermospheric relaxation time during QHF flares is responsible for sustained density enhancements and therefore needs to be considered one of the important drivers of satellite drag.

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准同源太阳耀斑及其对热层密度和卫星轨道阻力的影响

太阳活动区域的准同源耀斑（Quasi - Homologous Flaring， QHF）活动在较长时间内以周期性爆发的形式释放出强烈的电磁辐射。在这封信中，我们介绍了基于Swarm - A测量的周期性脉冲极紫外（EUV）加热对热层中性密度的影响以及由此产生的大气阻力对卫星的影响。在AR4366（2026年2月）和AR3664（2024年5月）的QHF期间，在海拔约460公里处的白天和夜间，分别观测到密度显著增强，分别达到25%-30%和50%-75%，持续数天。结果表明，在AR4366和AR3664 QHF事件期间，Swarm‐a的轨道衰减率分别从79.43 m/d增加到96.28 m/d，从19.91 m/d增加到42.43 m/d。在QHF耀斑期间，以比典型热层弛豫时间短的间隔重复的极紫外加热是造成持续密度增强的原因，因此需要被认为是卫星阻力的重要驱动因素之一。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Geophysical Research Letters 地学-地球科学综合

CiteScore

9.00

自引率

9.60%

发文量

1588

审稿时长

2.2 months

期刊介绍： Geophysical Research Letters (GRL) publishes high-impact, innovative, and timely research on major scientific advances in all the major geoscience disciplines. Papers are communications-length articles and should have broad and immediate implications in their discipline or across the geosciences. GRLmaintains the fastest turn-around of all high-impact publications in the geosciences and works closely with authors to ensure broad visibility of top papers.