| Title | Solar Energetic Electron Events Associated with Hard X-Ray Flares |
| Authors | Wang, Wen Wang, Linghua Krucker, Sam Mason, Glenn M. Su, Yang Bucik, Radoslav |
| Affiliation | Peking Univ, Sch Earth & Space Sci, Beijing 100871, Peoples R China Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA Univ Appl Sci Northwestern Switzerland, Inst 4D Technol, CH-5210 Windisch, Switzerland Johns Hopkins Univ, Appl Phys Lab, Johns Hopkins Rd, Laurel, MD 20723 USA Chinese Acad Sci, Purple Mt Observ, Key Lab Dark Matter & Space Astron, Nanjing 210023, Peoples R China Univ Sci & Technol China, Sch Astron & Space Sci, Hefei 230026, Peoples R China Southwest Res Inst, San Antonio, TX 78238 USA |
| Keywords | PARTICLE-ACCELERATION HEAVY-IONS SPECTRA RHESSI EMISSION ORIGIN RADIO SUN TEMPERATURES MECHANISM |
| Issue Date | Jun-2021 |
| Publisher | ASTROPHYSICAL JOURNAL |
| Abstract | We investigate 16 solar energetic electron (SEE) events measured by WIND/3DP with a double-power-law spectrum and the associated western hard X-ray (HXR) flares measured by RHESSI with good count statistics, from 2002 February to 2016 December. In all the 16 cases, the presence of an SEE power-law spectrum extending down to <= 5 keV at 1 au implies that the SEE source would be high in the corona, at a heliocentric distance of >= 1.3 solar radii, while the footpoint or footpoint-like emissions shown in HXR images suggest that the observed HXRs are likely produced mainly by HXR-producing electrons via thick-target bremsstrahlung processes very low in the corona. We find that for all the 16 cases, the estimated power-law spectral index of HXR-producing electrons is no less than the observed high-energy spectral index of SEEs, and it shows a positive correlation with the high-energy spectral index of SEEs. In addition, the estimated number of SEEs is only similar to 10(-4)-10(-2) of the estimated number of HXR-producing electrons at energies above 30 keV, but with a positive correlation between the two numbers. These results suggest that in these cases, SEEs are likely formed by upward-traveling electrons from an acceleration source high in the corona, while their downward-traveling counterparts may undergo a secondary acceleration before producing HXRs via thick-target bremsstrahlung processes. In addition, the associated He-3/He-4 ratio is positively correlated with the observed high-energy spectral index of SEEs, indicating a possible relation of the He-3 ion acceleration with high-energy SEEs. |
| URI | http://hdl.handle.net/20.500.11897/622611 |
| ISSN | 0004-637X |
| DOI | 10.3847/1538-4357/abefce |
| Indexed | SCI(E) |
| Appears in Collections: | 地球与空间科学学院 |
