E-Print Archive

There are 4507 abstracts currently viewable.


Search:

Advanced Search
Options
Main Page Add New E-Print Submitter
Information
Feedback
News Help/FAQ About Preferences
Manage Key Phrase
Notification
The magnetic connectivity of coronal shocks to the visible solar surface during long-duration gamma-ray events View all abstracts by submitter

Illya Plotnikov   Submitted: 2017-03-23 08:26

Context: Solar gamma-ray events measured near Earth can last several hours during so-called Long Duration Gamma Ray Flares (LDGRFs). LDGRFs suggest that a particle-acceleration mechanism operates over many hours to produce energetic protons that stream continually towards the solar surface. Coronal shocks, driven by the expansion of Coronal Mass Ejections (CMEs), could be the source of these energetic particles. For this hypothesis to work, the shock must be magnetically connected to the solar disk visible from Earth in order for particles accelerated at the shock to be channeled towards and impact the visible chromosphere. LDGRFs that occur when solar eruptions erupt on the far side of the Sun and during which the flare loops and footpoints are not visible from Earth, provide favourable case studies to isolate the possible role of shocks driven by CMEs in producing the LDGRFs. Aims: In this paper, we investigate if the spatial and temporal evolution of the coronal shocks, inferred from stereoscopic observations, could be the accelerators of the particles producing the LDGRFs. Methods: We analyse three CMEs that (1) erupted behind the solar limb viewed from Earth, (2) were associated with the early formation of coronal shocks measured by ground-based radio spectrographs, and (3) were associated with gamma-ray events measured by the Fermi-Large Area Telescope (LAT) instrument. A 3D triangulation technique, based on remote-sensing observations is employed to model the expansion of these three CME shocks from above the solar surface to the upper corona. Coupling the expansion model to different models of the coronal magnetic field allows us to derive the time-dependent distribution of shock Mach numbers and the magnetic connection of particles produced by the shock to the solar surface visible from Earth. Results: For all events, the reconstructed shock front was magnetically connected to the visible solar surface after the start of the flare and just before the onset of the >100 MeV gamma-ray emission observed by Fermi-LAT gamma-ray emission. The shock surface also exhibits super-critical Mach numbers required for significant particle energisation. The strongest gamma-ray emissions occur when the flanks of the shock exhibiting a quasi-perpendicular geometry are connected to the visible surface. Multi-point in-situ measurements of solar energetic particles (SEPs) during the events studied reveals that the flux of protons with energies between 10 and 100 MeV is highest for the fastest shock and the strongest LDGRF measured on 2014 Sep 1. Conclusion: This study provides further evidence that the high-energy protons producing the long duration high-energy -ray emission has likely the same CME shock origin as the solar energetic particles measured in interplanetary space.

Authors: Illya Plotnikov, Alexis P. Rouillard, Gerald H. Share
Projects: Fermi/GBM,Fermi/LAT,SDO-AIA,SoHO-LASCO,STEREO

Publication Status: Submitted to A&A
Last Modified: 2017-03-23 14:50
Go to main E-Print page  Coronal loop density profile estimated by forward modelling of EUV intensity  Dissipative instability in a partially ionised prominence slab  Edit Entry  Download Preprint  Delete Entry 

Key
Go to main E-Print pageGo to main E-Print page.
Previous AbstractPrevious Abstract.
Next AbstractNext Abstract.
Download PreprintDownload Preprint.
Submitter's HomepageSubmitters Homepage.
Edit EntryEdit Entry.
View All Abstracts By SubmitterView all abstracts by submitter.
Delete AbstractDelete abstract.

Latest Entries
The role and contribution of magnetic fields, characterized via their magnetic flux, to the statistical structuring of the solar atmosphere
Do periods of decayless kink oscillations of solar coronal loops depend on noise?
Automatic detection technique for solar filament oscillations in GONG data
Probing the Density Fine Structuring of the Solar Corona with Comet Lovejoy
Confined plasma transition from the solar atmosphere to the interplanetary medium
Extracting the Heliographic Coordinates of Coronal Rays using Images from WISPR/Parker Solar Probe
Two-spacecraft detection of short-period decayless kink oscillations of solar coronal loops
Genesis and Coronal-jet-generating Eruption of a Solar Minifilament Captured by IRIS Slit-raster Spectra
First detection of transverse vertical oscillation during the expansion of coronal loops
A New Position Calibration Method for MUSER Images
Sigmoid Formation Through Slippage of A Single J-shaped Coronal Loop
MHD Simulation of Homologous Eruptions from Solar Active Region 10930 Caused by Sunspot Rotation
Dropouts of Fully Stripped Ions in the Solar Wind: A Diagnostic for Wave Heating versus Reconnection
Plasma heating and nanoflare caused by slow-mode wave in a coronal loop
The Lyman-α Emission in a C1.4 Solar Flare Observed by the Extreme Ultraviolet Imager aboard Solar Orbiter
Imaging and Spectroscopic Observations of the Dynamic Processes in Limb Solar Flares
Evolution of the critical torus instability height and CME likelihood in solar active regions
A Magnetogram-matching Method for Energizing Magnetic Flux Ropes Toward Eruption
A 2D Model for Coronal Bright Points: Association with Spicules, UV bursts, Surges and EUV Coronal Jets
The relativistic solar particle event on 28 October 2021: Evidence of particle acceleration within and escape from the solar corona

Related Pages
MSU Solar Physics.
Max Millennium Science Mail Archive.
Max Millennium Message of the Day Mail Archive.
Max Millennium Flare Catalog

Archive Maintainer
Alisdair Davey



© 2000-2020 Solar Physics Group - Montana State University