000007511 001__ 7511
000007511 005__ 20250204104326.0
000007511 0247_ $$2DOI$$a10.3847/1538-4357/ad4640
000007511 037__ $$aSCART-2025-0110
000007511 100__ $$aWhite, Stephen M.
000007511 245__ $$aElectron Cyclotron Maser Emission and the Brightest Solar Radio Bursts
000007511 260__ $$c2024
000007511 520__ $$aThis paper investigates the incidence of coherent emission in solar radio bursts, using a revised catalog of 3800 solar radio bursts observed by the Nobeyama Radio Polarimeters from 1988 to 2023. We focus on the 1.0 and 2.0 GHz data, where radio fluxes of order 1010 Jy have been observed. Previous work has suggested that these bursts are due to electron cyclotron maser (ECM) emission. In at least one well-studied case, the bright emission at 1 GHz consists of arrowband spikes of millisecond duration. Coherent emission at 1 GHz can be distinguished from traditional incoherent gyrosynchrotron flare emission based on the radio spectrum: Gyrosynchrotron emission at 1 GHz usually has a spectrum rising with frequency, so bursts in which 1 GHz is stronger than higher-frequency measurements are unlikely to be incoherent gyrosynchrotron. Based on this criterion, it is found that for bursts exceeding 100 sfu, three-quarters of all bursts at 1 GHz and half of all 2 GHz bursts have a dominant coherent mission component, assumed to be ECM. The majority of the very bright bursts at 1 GHz are highly circularly polarized, consistent with a coherent emission mechanism, but not always 100% polarized. The frequency range from 1 to 2 GHz is heavily utilized for terrestrial applications, and these results are relevant for understanding the extreme flux levels that may impact such applications. Further, they provide a reference for comparison with the study of ECM emission from other stars and potentially exoplanets.
000007511 594__ $$aNO
000007511 6531_ $$aSolar flares
000007511 6531_ $$aSolar activity
000007511 6531_ $$aSolar radio emission
000007511 6531_ $$aSolar radio flares
000007511 700__ $$aShimojo, Masumi
000007511 700__ $$aIwai, Kazumasa
000007511 700__ $$aBastian, Timothy S.
000007511 700__ $$aFleishman, Gregory D.
000007511 700__ $$aGary, Dale E.
000007511 700__ $$aMagdalenic, Jasmina
000007511 700__ $$aVourlidas, Angelos
000007511 773__ $$c11$$n1$$pThe Astrophysical Journal$$v969$$y2024
000007511 8560_ $$fpavai.valliappan@ksb-orb.be
000007511 905__ $$apublished in
000007511 980__ $$aREFERD