来自南极洲的太阳耀斑的长基线甚低频观测
Long-Baseline VLF Observations of Solar Flares from Antarctica
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中文总结 AI 辅助
该研究利用南极洲保加利亚极地天文台的长基线甚低频观测，分析2025年1月24日至2月8日太阳耀斑观测数据，通过叠加时代分析去除日信号，揭示了耀斑相关扰动及X射线和甚低频峰值间的时间延迟，证明了长基线南极甚低频观测对耀斑监测的科学价值及存在的限制。
中文摘要 AI 辅助
我们展示了在南极洲利文斯顿岛的保加利亚极地天文台（圣克莱门特·奥赫里德斯基基地）获得的太阳耀斑诱发电离层扰动的长基线甚低频观测结果。利用21.4千赫（夏威夷NPM）和24.0千赫（缅因州NAA）的连续甚低频传输，通过超过11000公里的跨半球路径传播，我们分析了2025年1月24日至2月8日期间的太阳耀斑观测数据。通过叠加时代分析去除强烈的日信号后，我们分析了250次C级和M级耀斑的甚低频振幅中与耀斑相关的扰动及其与GOES软X射线通量的相关性。长传播路径提高了对耀斑驱动的D区电离变化的敏感性。观测结果揭示了清晰的、频率依赖的响应以及X射线和甚低频峰值之间可测量的时间延迟。这些延迟，包括强事件中接近零或负滞后的情况，突出了耀斑光谱特征和D区复合过程的作用。我们的结果证明了长基线南极甚低频观测对于检测和定时GOES级耀斑的科学价值，同时也突出了关键限制，如背景变异性和路径依赖的传播效应，这些必须进行量化才能进行可靠的基于甚低频的耀斑监测。
英文摘要
We present long-baseline Very Low Frequency (VLF) observations of solar flare-induced ionospheric disturbances obtained at the Bulgarian Polar Astronomical Observatory (St. Kliment Ohridski Base) on Livingston island, Antarctica. Using continuous VLF transmissions at 21.4 kHz (NPM, Hawaii) and 24.0 kHz (NAA, Maine), propagating over trans-hemispheric paths exceeding 11 000 km, we analyze observations of solar flares during the period 24 January-8 February 2025. After removing the strong diurnal signal via superposed epoch analysis, we analyse the flare-related perturbations in VLF amplitude and their correlation with GOES soft X-ray flux for 250 flares of C and M class. The long propagation paths provide enhanced sensitivity to flare-driven changes in D-region ionization. The observations reveal clear, frequency-dependent responses and measurable time delays between X-ray peaks and VLF extrema. These delays, including cases of near-zero or negative correlation lag for stronger events, are consistent with a possible role for flare spectral characteristics and D-region recombination processes, although alternative explanations related to waveguide propagation and signal-profile differences cannot presently be excluded. Our results demonstrate the scientific value of long-baseline Antarctic VLF observations for detecting and timing GOES-class flares, while also highlighting key limitations, such as background variability and path-dependent propagation effects, which must be quantified for reliable VLF-based flare monitoring.
发表机构
- Institute of Astronomy and NAO, Bulgarian Academy of Sciences（保加利亚科学院天体物理与国家天文台研究所）
- Technical University of Sofia（索菲亚理工大学）
- Nikola Vaptsarov Naval Academy（尼古拉·瓦普察罗夫海军学院）
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