E-Print Archive

There are 4310 abstracts currently viewable.


Advanced Search
Main Page Add New E-Print Submitter
News Help/FAQ About Preferences
Manage Key Phrase
* 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.

The effect of magnetic field on the damping of slow waves in the solar corona View all abstracts by submitter

Timothy James Duckenfield   Submitted: 2020-11-23 05:24

Context: Slow magnetoacoustic waves are routinely observed in astrophysical plasma systems such as the solar corona, and are usually seen to damp rapidly. As a slow wave propagates through a plasma, it modifies the equilibrium quantities of density, temperature, and magnetic field. In the corona and other plasma systems, the thermal equilibrium is comprised of a balance between continuous heating and cooling processes, the magnitudes of which vary with density, temperature and magnetic field. Thus the wave may induce a misbalance between these competing processes. Its back reaction on the wave has been shown to lead to dispersion, and amplification or damping, of the wave. Aims: This effect of heating/cooling misbalance has previously been studied in the infinite magnetic field approximation, in a plasma whose thermal equilibrium comprises of optically thin radiative losses and field-aligned thermal conduction, balanced by an (unspecified) heating process. In this work we extend this analysis by considering a non-zero beta plasma. The importance of the effect of magnetic field in the rapid damping of slow waves in the solar corona is evaluated, and compared to the effects of thermal conduction. Methods: A linear perturbation under the thin flux tube approximation is considered, and a dispersion relation describing the slow magnetoacoustic modes is found. The dispersion relationís limits of strong non-adiabaticity and weak non-adiabaticity are studied. The characteristic timescales are calculated for plasma systems with a range of typical coronal densities, temperatures and magnetic field strengths. Results: The number of timescales characterising the effect of misbalance is found to remain at two, as with the infinite magnetic field case. In the non-zero beta case, these two timescales correspond to the partial derivatives of the combined heating/cooling function with respect to constant gas pressure and with respect to constant magnetic pressure. The predicted damping times of slow waves from thermal misbalance in the solar corona are found to be of the order of 10Ė100 minutes, coinciding with the wave periods and damping times observed. Moreover the slow wave damping by thermal misbalance is found to be comparable to the damping by field-aligned thermal conduction. The change in damping with plasma-beta is complex and depends on the coronal heating functionís dependence upon the magnetic field in particular. Nonetheless we show that in the infinite field limit, the wave dynamics is insensitive to the dependence of the heating function on the magnetic field, and this approximation is found to be valid in the corona so long as the magnetic field strength is greater than approximately 10G for quiescent loops and plumes, and 100G for hot and dense loops. Conclusions: Thermal misbalance may damp slow magnetoacoustic waves rapidly in much of the corona, and its inclusion in our understanding of slow mode damping may resolve discrepancies between observations and theory relying on compressive viscosity and thermal conduction alone.

Authors: T. J. Duckenfield, D. Y. Kolotkov, and V. M. Nakariakov
Projects: None

Publication Status: A&A (accepted)
Last Modified: 2020-11-25 12:04
Go to main E-Print page  Non-Neutralized Electric Current of Active Regions Explained as a Projection Effect  Soft X-Ray Observations of Quiescent Solar Active Regions using Novel Dual-zone Aperture X-ray Solar Spectrometer (DAXSS)  Edit Entry  Download Preprint  Submitter's Homepage Delete Entry 

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
Thermal-nonthermal energy partition in solar flares derived from X-ray, EUV, and bolometric observations
From Pseudostreamer Jets to Coronal Mass Ejections: Observations of the Breakout Continuum
Designing a New Coronal Magnetic Field Energy Diagnostic
A Three-Dimensional Velocity of an Erupting Prominence Prior to a Coronal Mass Ejection
Spectroscopic observations of a flare-related coronal jet
Catalog of Solar Failed Eruptions and Other Dynamic Features Registered by SDO/AIA
The non-Fourier image reconstruction method for the STIX instrument
Observation and Modeling of Solar Jets
Challenges and Advances in Modeling of the Solar Atmosphere: A White Paper of Findings and Recommendations
Non-equilibrium Flux Rope Formation by Confined Flares Preceding a Solar Coronal Mass Ejection
Radio Measurements of the Magnetic Field in the Solar Chromosphere and the Corona
A Fast, Simple, Robust Algorithm for Coronal Temperature Reconstruction
Nonlinear Alfvén Wave Model of Stellar Coronae and Winds from the Sun to M dwarfs
Possibility of Diagnostics of the Beginning of Solar Cycle 25 Based on Its Precursors at Mid-Heliolatitudes
The chromospheric component of coronal bright points. Coronal and chromospheric responses to magnetic-flux emergence
Structure of the Solar Atmosphere: A Radio Perspective
Signatures of Cross-sectional Width Modulation in Solar Spicules due to Field-aligned Flows
ALMA and IRIS Observations of the Solar Chromosphere II: Structure and Dynamics of Chromospheric Plage
ALMA and IRIS Observations of the Solar Chromosphere I: an On-Disk Type II Spicule
Evolution of a Steamer-Blowout CME as Observed by Imagers on Parker Solar Probe and the Solar Terrestrial Relations Observatory

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