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<p>We report on 27 coronal mass ejections (CMEs) observed in the inner corona (roughly ≤ 2 solar radii (R<sub>s</sub>)) at the Mauna Loa Solar Observatory (MLSO) with the K-Coronagraph (K-Cor) from late 2013 until November 2022, when MLSO operations were suspended due to a volcanic eruption. All these CMEs were associated with solar energetic particle (SEP) events including ∼ 25&#xa0;MeV protons observed by spacecraft at different locations in the inner heliosphere (≤ 1 astronomical unit (au). We analyzed the characteristics of these CMEs and compared them to a sample of CMEs observed by K-Cor during the same period with no known SEPs. We found that both samples of SEP and non-SEP CMEs expanded in width between the inner and middle corona (&gt; 2 R<sub>s</sub>), where they were observed by spacebased coronagraphs. However, the average and the median widths for the drivers of SEP CMEs were a factor of two larger than for the non-SEP CME drivers in both the inner and middle corona. Similarly, we found that the average speed of the SEP CMEs in the inner corona was more than a factor of two faster than the average for non-SEP CMEs, and almost a factor of two faster in the middle corona. Most of the CMEs (&gt; 80%) were accelerating in the inner corona for both SEP and non-SEP samples, though the average acceleration in the inner corona for the SEP CMEs was almost a factor three larger than for the non-SEP sample. The mass estimates provided in the Coordinated Data Analysis Workshops (CDAW) catalogue for the two samples also shows that the average for SEP CMEs was almost a factor three larger than for the non-SEP sample. The event of 2021-11-01 is presented as an example of an SEP CME included in this study. One of the 27 SEPs registered S1 on the National Oceanic and Atmospheric Administration (NOAA) solar radiation storm scale (S-scale) in the near-Earth environment, and several others were detected by the NOAA Geostationary Operational Environmental Satellites (GOES) spacecraft at lower levels. Additionally, three of the SEP events detected by the Solar Terrestrial Relations Observatory (STEREO-A) when far from Earth would have exceeded the S1 storm level. When observing, MLSO K-Cor provides near-real-time monitoring and alerts of CMEs appearing in the inner corona, hence it can provide an earlier warning than most spacebased coronagraphs of a potentially SEP-associated CME to robotic and human explorers who are concerned about the abrupt appearance of SEPs.</p>

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Mauna Loa Solar Observatory K-Cor Coronagraph Observations of Coronal Mass Ejections Associated with Solar Energetic Particles

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  • 发表日期：

    2026年7月10日

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  • O. C. St. Cyr,
  • I. G. Richardson,
  • J. T. Burkepile,
  • M. Galloy,
  • T. Nieves-Chinchilla,
  • B. J. Thompson

摘要

We report on 27 coronal mass ejections (CMEs) observed in the inner corona (roughly ≤ 2 solar radii (Rs)) at the Mauna Loa Solar Observatory (MLSO) with the K-Coronagraph (K-Cor) from late 2013 until November 2022, when MLSO operations were suspended due to a volcanic eruption. All these CMEs were associated with solar energetic particle (SEP) events including ∼ 25 MeV protons observed by spacecraft at different locations in the inner heliosphere (≤ 1 astronomical unit (au). We analyzed the characteristics of these CMEs and compared them to a sample of CMEs observed by K-Cor during the same period with no known SEPs. We found that both samples of SEP and non-SEP CMEs expanded in width between the inner and middle corona (> 2 Rs), where they were observed by spacebased coronagraphs. However, the average and the median widths for the drivers of SEP CMEs were a factor of two larger than for the non-SEP CME drivers in both the inner and middle corona. Similarly, we found that the average speed of the SEP CMEs in the inner corona was more than a factor of two faster than the average for non-SEP CMEs, and almost a factor of two faster in the middle corona. Most of the CMEs (> 80%) were accelerating in the inner corona for both SEP and non-SEP samples, though the average acceleration in the inner corona for the SEP CMEs was almost a factor three larger than for the non-SEP sample. The mass estimates provided in the Coordinated Data Analysis Workshops (CDAW) catalogue for the two samples also shows that the average for SEP CMEs was almost a factor three larger than for the non-SEP sample. The event of 2021-11-01 is presented as an example of an SEP CME included in this study. One of the 27 SEPs registered S1 on the National Oceanic and Atmospheric Administration (NOAA) solar radiation storm scale (S-scale) in the near-Earth environment, and several others were detected by the NOAA Geostationary Operational Environmental Satellites (GOES) spacecraft at lower levels. Additionally, three of the SEP events detected by the Solar Terrestrial Relations Observatory (STEREO-A) when far from Earth would have exceeded the S1 storm level. When observing, MLSO K-Cor provides near-real-time monitoring and alerts of CMEs appearing in the inner corona, hence it can provide an earlier warning than most spacebased coronagraphs of a potentially SEP-associated CME to robotic and human explorers who are concerned about the abrupt appearance of SEPs.