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VERSION:2.0
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METHOD:PUBLISH
BEGIN:VEVENT
DTSTAMP:20260309T062956Z
UID:https://www.mps.mpg.de/events/25158/7840830
DTSTART:20200220T100000Z
DTEND:20200220T110000Z
CLASS:PUBLIC
CREATED:20200619T123806Z
DESCRIPTION: During a solar flare\, it is believed that reconnection takes 
 place in the corona followed by fast energy transport to the chromosphere.
  The resulting intense heating strongly disturbs the chromospheric structu
 re and induces complex radiation hydrodynamic effects. Interpreting the ph
 ysics of the flaring solar atmosphere is one of the most challenging tasks
  in solar physics. We present a novel deep learning approach\, an invertib
 le neural network\, to understanding the chromospheric physics of a flarin
 g solar atmosphere via the inversion of observed solar line profiles in H&
 amp\;alpha\; and Ca II &amp\;lambda\;8542. The network is trained using fl
 are simulations from the 1D radiation hydrodynamic code RADYN as the expec
 ted atmosphere and line profile. This model is then applied to whole image
 s from an observation of an M1.1 solar flare taken with the Swedish 1 m So
 lar Telescope/CRisp Imaging SpectroPolarimeter instrument. The inverted at
 mospheres obtained from observations provide physical information on the e
 lectron number density\, temperature and bulk velocity flow of the plasma 
 throughout the solar atmosphere ranging in height from 0 to 10 Mm. Our met
 hod can invert a 1k x 1k field-of-view in approximately 30 minutes and we 
 show results from the whole image inversions and error calculations on the
  inversions. Furthermore\, we delve into the mammoth task of analysing the
  wealth of data we have accumulated through these inversions. The magnetic
  Rayleigh–Taylor instability is a fundamental MHD instability and recent
  observations show that this instability develops in the solar prominences
 . We analyze the observations from Solar Dynamic Observatory/Atmospheric I
 maging Assembly of a MRT unstable loop-like prominence. Initially\, some s
 mall-scale perturbations are developed horizontally and vertically at the 
 prominence-cavity interface. These perturbations are associated with the h
 ot and low dense coronal plasma as compared to the surrounding prominence.
  The interface supports magneto-thermal convection process\, which acts as
  a buoyancy to launch the hot and low denser plumes (P1 and P2) propagatin
 g with the speed of 35–46 km s-1 in the overlying prominence. The self-s
 imilar plume formation initially shows the growth of a linear MRT-unstable
  plume (P1)\, and thereafter the evolution of a nonlinear single-mode MRT-
 unstable second plume (P2). A differential emission measure analysis shows
  that plumes are less denser and hotter than the prominence. We have estim
 ated the observational growth rate for both the plumes as 1.32±0.29×10
 −3 s−1 and 1.48±0.29×10^−3 s^−1\, respectively\, which are compa
 rable to the estimated theoretical growth rate (1.95×10^−3 s^−1). Lat
 er\, these MRT unstable plumes get stabilize via formation of rolled (vort
 ex-like) plasma structures at the prominence-cavity interface in the downf
 alling plasma. These rolled-plasma structures depict Kelvin-Helmholtz inst
 ability\, which corresponds to the nonlinear phase of MRT instability. How
 ever\, even after the full development of MRT instability\, the overlying 
 prominence is not erupted. Later\, a Rayleigh-Taylor unstable tangled plas
 ma thread is evident in the rising segment of this prominence. This tangle
 d thread is subjected to the compression between eruption site and overlyi
 ng dense prominence at the interface. This compression initiates strong sh
 ear at the prominence-cavity interface and causes Kelvin-Helmholtz vortex-
 like structures. Due to this shear motion\, the plasma downfall is occurre
 d at the right part of the prominence–cavity boundary. It triggers the c
 haracteristic KH unstable vortices and MRT-unstable plasma bubbles propaga
 ting at different speeds and merging with each other. The shear motion and
  lateral plasma downfall may initiate hybrid KH-RT instability there.\nVor
 tragende(r): John Armstrong
LAST-MODIFIED:20260220T073033Z
LOCATION:Max-Planck-Institut für Sonnensystemforschung\, Raum: Aquila + Bo
 otes
ORGANIZER;CN=Pradeep Chitta:mailto:
SUMMARY:ESPOS: ESP Online Seminar: Learning to Invert Solar Flares with RAD
 YN Physics
URL;VALUE=URI:https://www.mps.mpg.de/events/25158/7840830
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