E-Print Archive

There are 4236 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
* News 04/04/20 * The archive is using a new backend database. This has thrown up a few SQL errors in the last few days. If you have any issues please email adavey@nso.edu with either the number of eprint you are trying to edit or a link to your preprint.

Modelling Mg II During Solar Flares. II. Non-equilibrium Effects View all abstracts by submitter

Graham Kerr   Submitted: 2019-09-30 19:15

To extract the information that the Mg II NUV spectra (observed by the Interface Region Imaging Spectrograph; IRIS), carries about the chromosphere during solar flares, and to validate models of energy transport via model-data comparison, forward modelling is required. The assumption of statistical equilibrium is typically used to obtain the atomic level populations from snapshots of flare atmospheres, due to computational necessity. However it is possible that relying on statistical equilibrium could lead to spurious results. We compare solving the atomic level populations via statistical equilibrium versus a non-equilibrium time-dependent approach. This was achieved using flare simulations from RADYN alongside the minority species version, MS_RADYN, from which the time-dependent Mg II atomic level populations and radiation transfer were computed in complete frequency redistribution. The impacts on the emergent profiles, lightcurves, line ratios, and formation heights are discussed. In summary we note that non-equilibrium effects during flares are typically important only in the initial stages and for a short period following the cessation of the energy injection. An analysis of the timescales of ionisation equilibrium reveals that for most of the duration of the flare, when the temperatures and densities are sufficiently enhanced, the relaxation timescales are short (τreleax<0.1 s), so that the equilibrium solution is an adequate approximation. These effects vary with the size of the flare, however. In weaker flares effects can be more pronounced. We recommend that non-equilibrium effects be considered when possible, but that statistical equilibrium is sufficient at most stages of the flare.

Authors: Kerr, Graham S., Carlsson, Mats and Allred, J.C.
Projects: None

Publication Status: Accepted in the Astrophysical Journal
Last Modified: 2019-10-02 10:40
Go to main E-Print page  Real-time solar image classification: assessing spectral, pixel-based approaches  Calibration of the Instrumental Crosstalk for the Near-IR Imaging Spectropolarimeter at the NST  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
Sunquake with a second-bounce, other sunquakes and emission associated with X9.3 flare of 6 September 2017. II. Proposed interpretation
f-mode strengthening from a localized bipolar subsurface magnetic field
Imaging and spectral study on the null point of a fan-spine structure during a solar flare
Forecasting Solar Cycle 25 Using Deep Neural Networks
An Observational Test of Solar Plasma Heating by Magnetic Flux Cancellation
The Drivers of Active Region Outflows into the Slow Solar Wind
HXR emission from an activated flux rope and subsequent evolution of an eruptive long duration solar flare
A Survey of Computational Tools in Solar Physics
Sunquake with a second bounce, other sunquakes, and emission associated with the X9.3 flare of 6 September 2017. I. Observations
The PDFI_SS Electric Field Inversion Software
Spatial Distribution of Origin of Umbral Waves in a Sunspot Umbra
A Unique Resource for Solar Flare Diagnostic Studies: the SMM Bent Crystal Spectrometer
Inferring Vector Magnetic Fields from Stokes Profiles of GST/NIRIS Using a Convolutional Neural Network
Global Energetics of Solar Flares, X. Petschek Reconnection Rate and Alfvén Mach Number of Magnetic Reconnection Outflows
Transverse coronal loop oscillations excited by homologous circular-ribbon flares
Temporal evolution of oscillating coronal loops
Intrusion of Magnetic Peninsula toward the Neighboring Opposite-polarity Region That Triggers the Largest Solar Flare in Solar Cycle 24
On the Relationship Between Transit Time of ICMEs and Strength of the Initiated Geomagnetic Storms
Standing kink waves in sigmoid solar coronal loops: implications for coronal seismology
Excitation of negative energy surface magnetohydrodynamic waves in an incompressible cylindrical plasma

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