MHD simulation of prominence-cavity system and forward modeling of COSMO/LC line-of-sight magnetic field measurement
Abstract
We present magnetohydrodynamic simulation of the evolution from quasi-equilibrium to onset of eruption of a twisted, prominence-forming coronal magnetic flux rope underlying a corona streamer. The flux rope is built up by an imposed flux emergence at the lower boundary. During the quasi-static phase of the evolution, we find the formation of a prominence-cavity system with qualitative features resembling observations, as shown by the synthetic SDO/AIA EUV images with the flux rope observed above the limb viewed nearly along its axis. The cavity contains substructures including “U”-shaped or horn-liked features extending from the prominence enclosing a central “cavity” on top of the prominence. The prominence condensations form in the dips of the highly twisted field lines due to runaway radiative cooling and the cavity is formed by the density depleted portions of the prominence-carrying field lines extending up from the dips. The flux rope eventually erupts as its central part rises quasi-statically to a critical height, producing a CME with associated prominence eruption. Using the MHD model of the prominence-cavity system, we carry out forward synthesis of the circular polarization signal of the Fe XIII emission line at 1074.7 nm as would be measured by the proposed COronal Solar Magnetism Observatory (COSMO) Large Coronagraph (LC) and infer the line-of-sight (LOS) magnetic field, with the simulated flux rope observed above the limb viewed linearly along its length. We find that the COSMO/LC can detect a significant LOS magnetic field from the flux rope with the measurement most sensitive to the region surrounding the prominence, i.e. the prominence horn region in the cavity. The measurement can detect an out-moving LOS field during the slow rise phase up to the onset of eruption.
- Publication:
-
Solar Heliospheric and INterplanetary Environment (SHINE 2019)
- Pub Date:
- May 2019
- Bibcode:
- 2019shin.confE..70F