Abstracts > Abstract list by author > Fang Xia

We use a 2.5-dimensional, fully thermodynamically and magnetohydrodynamically
compatible model to imitate the formation process of normal polarity prominences
on top of initially linear force-free arcades above photospheric neutral lines.
Based on sheared magnetic arcades hosting chromospheric, transition region, and
coronal plasma, we perform a series of numerical simulations to do a parameter
survey for multi-dimensional evaporation-condensation prominence models.
The investigated parameters include the shearing angle of the magnetic arcade,
the strength and spatial range of the localized chromospheric heating, and cover
symmetric and asymmetric circumstances.
In the symmetric cases, we analyze the growth rate of accumulated prominence
mass, overall force balance, and morphology and how these aspects relate to the
input heating parameters. Some of our modeled prominences develop additional
internal structure, with the side boundaries of the prominence resembling sawteeth,
when the magnetic field of the arcade is strong. Indeed, when the lateral growing
prominence can not bend the arched loops fast enough, segments of the prominence
body residing in self-created magnetic dips fall down to the chromosphere
along the arched loops. This drags extra mass from inside the magnetic dips to
stream down until all prominence mass in the affected loops drains to the chromosphere.
Consecutively, the evacuated loops reform condensations, and this phenomenon
propagates from lower to higher loops. This realizes a down-streaming
channel adjacent to an up-streaming channel, reforming the prominence as it rises,
and we suggest these long-lived streams connecting the prominence and the chromosphere
resemble the barbs of prominences. They also shed light on the mass
recycling puzzle of prominences in general.
In asymmetric cases, We demonstrate how thermal instability and catastrophic
cooling can induce a spectacular display of in-situ forming blob-like
condensations which then start their intimate dynamical ballet on top of
initially linear force-free arcades above photospheric neutral lines. Our
magnetic arcades host chromospheric, transition region, and coronal plasma, and
by following coronal rain dynamics for over 80 minutes physical time, we collect
enough statistics to quantify blob widths, lengths, velocity distributions, and
other characteristics which directly match with modern observational knowledge.
Our virtual coronal rain displays the deformation of blobs into
$V$-shaped like features, interactions of blobs due to mostly pressure-mediated
levitations, and gives the first views on blobs which evaporate in situ, or get
siphoned over the apex of the background arcade.