Variation of Doppler velocity with non-thermal line width in a gravitationally stratified plasma
Abstract
Magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere. These waves play an important role in the heating of solar corona. Recently, an apparent discrepancy is observed in the Alfvénic wave amplitudes measured by the Coronal Multi-channel Polarimeter (CoMP) compared to those measured by the Hinode and the Solar Dynamics Observatory (SDO). This discrepancy was attributed to a large line-of-sight superposition and low spatial resolution of the CoMP, which may lead to low wave amplitudes and large non-thermal line widths. A wedge-shape correlation is also observed between root mean square Doppler velocity and mean non-thermal line width. We investigate this scenario by performing a 3D MHD simulation of a gravitationally stratified transversely inhomogenous plasma subjected to the unidirectionally propagating MHD waves. Here, we present the results of this simulation forward modelled with the FoMo for Fe XIII (10747 Å) emission line to study the variation of Doppler velocities with non-thermal line widths. We perform the random integration over different line-of-sights angles across and along the simulation box. We degrade the spatial resolution of the simulation box to the spatial resolution of the CoMP and compare Doppler velocities and non-thermal line widths at different heights. We compare our results with previous studies as well as with observations made by the CoMP and find a fairly good match between them.
- Publication:
-
Catalyzing Solar Connections
- Pub Date:
- November 2018
- Bibcode:
- 2018csc..confE..70P