E-Print Archive

There are 4354 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 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 

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
Energy budget of plasma motions, heating, and electron acceleration in a three-loop solar flare
Space weather: the solar perspective - an update to Schwenn (2006)
Mixed properties of slow magnetoacoustic and entropy waves in a plasma with heating/cooling misbalance
The morphology of average solar flare time profiles from observations of the Sun's lower atmosphere
Indications of stellar coronal mass ejections through coronal dimmings
Could switchbacks originate in the lower solar atmosphere? II. Propagation of switchbacks in the solar corona
Solar large-scale magnetic field and cycle patterns in solar dynamo
Three-dimensional magnetic reconnection in astrophysical plasmas
Energy partition in a confined flare with an extreme-ultraviolet late phase
Alfvén wave heating in partially ionized thin threads of solar prominences
He I 10830Ň Dimming During Solar Flares, I: The Crucial Role of Non-Thermal Collisional Ionisations
Separating aa-index into Solar and Hale Cycle Related Components Using Principal Component Analysis
Inward Propagating Plasma Parcels in the Solar Corona: Models with Aerodynamic Drag, Ablation, and Snowplow Accretion
Energetics and 3-D Structure of Elementary Events in Solar Coronal Heating
Stellar Superflares Observed Simultaneously with Kepler and XMM-Newton
Medium-term predictions of F10.7 and F30 cm solar radio flux with the adaptive Kalman filter
Resonances in a Coronal Loop Driven by Torsional Alfvén Waves Propagating from the Photosphere
Effects of external flow on resonant absorption of coronal loop kink oscillations driven by an external fast wave: Selective excitation problem
Emerging Dimming as Coronal Heating Episodes
Proxy-Based Prediction of Solar Extreme Ultraviolet Emission using Deep Learning

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