Solar Ultraviolet Bursts

• DOI: 10.1007/s11214-018-0551-0
• Publication Date: 2018-11-06T09:40:59Z
• Authors: Peter R. Young; Hui Tian; Hardi Peter; Robert J. Rutten; Chris J. Nelson; Zhenghua Huang; Brigitte Schmieder; Gregal J. M. Vissers; Shin Toriumi; Luc H. M. Rouppe ...; Maria S. Madjarska; Sanja Danilovic; Arkadiusz Berlicki; L. P. Chitta; Mark C. M. Cheung; Chad Madsen; Kevin P. Reardon; Yukio Katsukawa; Petr Heinzel
• Keywords: H-ALPHA; FEATURES; FOS: Physical sciences; Astronomy & Astrophysics; 530; ELLERMAN BOMBS; Sun: activity; MAGNETIC RECONNECTION; Sun: transition region; Solar and Stellar Astrophysics (astro-ph.SR); TRANSITION-REGION BLINKERS; EXPLOSIVE EVENTS; [PHYS]Physics [physics]; Science & Technology; IV BURSTS; Sun: UV radiation; 520; QUIET-SUN; Astrophysics - Solar and Stellar Astrophysics; 13. Climate action; Physical Sciences; SI-IV; EMERGING FLUX; [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph]; [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]; Sun: atmosphere

Review article accepted for publication in Space Science Reviews<br/>The term "ultraviolet (UV) burst" is introduced to describe small, intense, transient brightenings in ultraviolet images of solar active regions. We inventorize their properties and provide a definition based on image sequences in transition-region lines. Coronal signatures are rare, and most bursts are associated with small-scale, canceling opposite-polarity fields in the photosphere that occur in emerging flux regions, moving magnetic features in sunspot moats, and sunspot light bridges. We also compare UV bursts with similar transition-region phenomena found previously in solar ultraviolet spectrometry and with similar phenomena at optical wavelengths, in particular Ellerman bombs. Akin to the latter, UV bursts are probably small-scale magnetic reconnection events occurring in the low atmosphere, at photospheric and/or chromospheric heights. Their intense emission in lines with optically thin formation gives unique diagnostic opportunities for studying the physics of magnetic reconnection in the low solar atmosphere. This paper is a review report from an International Space Science Institute team that met in 2016-2017.<br/>