_version_ 1866918160555311104
author Mondal, Surajit
Chen, Bin
Yu, Sijie
Chen, Xingyao
Zhang, Peijin
Gary, Dale
Anderson, Marin M.
Bowman, Judd D.
Byrne, Ruby
Catha, Morgan
Chhabra, Sherry
Addario, Larry D
Davis, Ivey
Dowell, Jayce
Hallinan, Gregg
Harnach, Charlie
Hellbourg, Greg
Hickish, Jack
Hobbs, Rick
Hodge, David
Hodges, Mark
Huang, Yuping
Isella, Andrea
Jacobs, Daniel C.
Kemby, Ghislain
Klinefelter, John T.
Kolopanis, Matthew
Kosogorov, Nikita
Lamb, James
Law, Casey
Mahesh, Nivedita
Donnell, Brian O
Posner, Corey
Powell, Travis
Prayag, Vinand
Rizo, Andres
Wolf, Andrew Romero
Shi, Jun
Taylor, Greg
Trim, Jordan
Virgin, Mike
Vydula, Akshatha
Weinreb, Sandy
White, Scott
Woody, David
Zentmeyer, Thomas
author_facet Mondal, Surajit
Chen, Bin
Yu, Sijie
Chen, Xingyao
Zhang, Peijin
Gary, Dale
Anderson, Marin M.
Bowman, Judd D.
Byrne, Ruby
Catha, Morgan
Chhabra, Sherry
Addario, Larry D
Davis, Ivey
Dowell, Jayce
Hallinan, Gregg
Harnach, Charlie
Hellbourg, Greg
Hickish, Jack
Hobbs, Rick
Hodge, David
Hodges, Mark
Huang, Yuping
Isella, Andrea
Jacobs, Daniel C.
Kemby, Ghislain
Klinefelter, John T.
Kolopanis, Matthew
Kosogorov, Nikita
Lamb, James
Law, Casey
Mahesh, Nivedita
Donnell, Brian O
Posner, Corey
Powell, Travis
Prayag, Vinand
Rizo, Andres
Wolf, Andrew Romero
Shi, Jun
Taylor, Greg
Trim, Jordan
Virgin, Mike
Vydula, Akshatha
Weinreb, Sandy
White, Scott
Woody, David
Zentmeyer, Thomas
contents Decades of solar coronal observations have provided substantial evidence for accelerated particles in the corona. In most cases, the location of particle acceleration can be roughly identified by combining high spatial and temporal resolution data from multiple instruments across a broad frequency range. In almost all cases, these nonthermal particles are associated with quiescent active regions, flares, and coronal mass ejections (CMEs). Only recently, some evidence of the existence of nonthermal electrons at locations outside these well-accepted regions has been found. Here, we report for the first time multiple cases of transient nonthermal emissions, in the heliocentric range of $\sim 3-7R_\odot$, which do not have any obvious counterparts in other wavebands, like white-light and extreme ultra-violet. These detections were made possible by the regular availability of high dynamic range low-frequency radio images from the Owens Valley Radio Observatory's Long Wavelength Array. While earlier detections of nonthermal emissions at these high heliocentric distances often had comparable extensions in the plane-of-sky, they were primarily been associated with radio CMEs, unlike the cases reported here. Thus, these results add on to the evidence that the middle corona is extremely dynamic and contains a population of nonthermal electrons, which is only becoming visible with high dynamic range low-frequency radio images.
format Preprint
id arxiv_https___arxiv_org_abs_2510_12658
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Enigmatic centi-SFU and mSFU nonthermal radio transients detected in the middle corona
Mondal, Surajit
Chen, Bin
Yu, Sijie
Chen, Xingyao
Zhang, Peijin
Gary, Dale
Anderson, Marin M.
Bowman, Judd D.
Byrne, Ruby
Catha, Morgan
Chhabra, Sherry
Addario, Larry D
Davis, Ivey
Dowell, Jayce
Hallinan, Gregg
Harnach, Charlie
Hellbourg, Greg
Hickish, Jack
Hobbs, Rick
Hodge, David
Hodges, Mark
Huang, Yuping
Isella, Andrea
Jacobs, Daniel C.
Kemby, Ghislain
Klinefelter, John T.
Kolopanis, Matthew
Kosogorov, Nikita
Lamb, James
Law, Casey
Mahesh, Nivedita
Donnell, Brian O
Posner, Corey
Powell, Travis
Prayag, Vinand
Rizo, Andres
Wolf, Andrew Romero
Shi, Jun
Taylor, Greg
Trim, Jordan
Virgin, Mike
Vydula, Akshatha
Weinreb, Sandy
White, Scott
Woody, David
Zentmeyer, Thomas
Solar and Stellar Astrophysics
Decades of solar coronal observations have provided substantial evidence for accelerated particles in the corona. In most cases, the location of particle acceleration can be roughly identified by combining high spatial and temporal resolution data from multiple instruments across a broad frequency range. In almost all cases, these nonthermal particles are associated with quiescent active regions, flares, and coronal mass ejections (CMEs). Only recently, some evidence of the existence of nonthermal electrons at locations outside these well-accepted regions has been found. Here, we report for the first time multiple cases of transient nonthermal emissions, in the heliocentric range of $\sim 3-7R_\odot$, which do not have any obvious counterparts in other wavebands, like white-light and extreme ultra-violet. These detections were made possible by the regular availability of high dynamic range low-frequency radio images from the Owens Valley Radio Observatory's Long Wavelength Array. While earlier detections of nonthermal emissions at these high heliocentric distances often had comparable extensions in the plane-of-sky, they were primarily been associated with radio CMEs, unlike the cases reported here. Thus, these results add on to the evidence that the middle corona is extremely dynamic and contains a population of nonthermal electrons, which is only becoming visible with high dynamic range low-frequency radio images.
title Enigmatic centi-SFU and mSFU nonthermal radio transients detected in the middle corona
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2510.12658