Probing the solar corona with Sun-grazing comets: comparing MHDsimulations with EUV observations
Abstract
Sun -grazing comets can dive within one solar radii of the Sun 's surface. The cometary materials expand along the comet's orbit, and undergo various stages of fierce thermal-chemical reactions on the scales of seconds to minutes. These reactions ionize cometary ions through successive charge states , which is revealed by certain emission lines in the AIA images. Such plasma reaction processes are significantly affected by the transient structures in the corona, and thus these structures are revealed by the structures and shapes of the comet tail. We combine three numerical models: a global corona model, particle transportation model, and cometary plasma interaction model into one framework to simulate the interaction of Sun -grazing comets in the low corona. In our framework, cometary ejecta are vaporized and then ionized via multiple channels, and then confined by the coronal magnetic field. Constrained by imaging observations of the and cometary interaction images, we apply our framework to trace back to the local condition of the ambient corona, and its spatiotemporal variation. Previously, our model confirmed the importance of the ambient magnetic field vector in shaping the tail. In this study, we use the C/2011 W3 (Lovejoy) perihelion to determine the local plasma and field conditions in the corona. Our framework is capable of resolving structures from thousands of meters to tens of million meters, so we can identify the fine spatial variations in plasma density and magnetic field intensity, which may be visible in future/on-going close-up coronal observations.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSH13A..03J
- Keywords:
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- 7509 Corona;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7513 Coronal mass ejections;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7594 Instruments and techniques;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY