Mats Carlsson
(Institute of Theoretical Astrophysics, University of Oslo)
22/06/2016, 09:00
The chromosphere is arguably the most difficult and least
understood domain of solar
physics. All at once it represents the transition from
optically thick to thin
radiation escape, from gas-pressure domination to
magnetic-pressure domination, from
neutral to ionised state, from MHD to plasma physics, and
from near-equilibrium
(LTE") to non-equilibrium conditions. The...
Vanessa Polito
(University of Cambridge)
22/06/2016, 09:30
The intensity of the OIV and SIV intercombination lines around 1400 Å observed with
the Interface Region Imaging Spectrograph (IRIS) provide a useful tool to diagnose
the electron number density in the solar transition region plasma. We measure the
electron density in a variety of solar features, including a loop and a bright point
in the AR NOAA 12356 and at the ribbons of the...
Andrii Sukhorukov
(Institutet för solfysik, Stockholms universitet)
22/06/2016, 09:50
We studied the formation of the most practically important resonance lines such as H
I Ly-a, Mg II k&h, and Ca II K&H in the chromosphere using 3D MHD snapshots produced
by the Bifrost numerical code. For this purpose, we implemented effects of partial
redistribution (PRD) using the hybrid approximation of Leenaarts et al. (2012) into
our radiative transfer code. We discuss some technical...
Haruhisa Iijima
(Institute for Space-Earth Environmental Research (ISEE), Nagoya University)
22/06/2016, 10:10
A three-dimensional simulation by the Tokyo code (tentative name) is presented to
investigate the effect of three-dimensionality on the scale of chromospheric jets and
the dependence on the photospheric magnetic field structure. We newly develop a
numerical code for the radiation magnetohydrodynamic modeling of solar atmosphere.
The code includes the effect of non-local radiative transfer...
Hardi Peter
(MPI for Solar System Research)
22/06/2016, 11:15
There is an everlasting mass cycle between the chromosphere
and the upper atmosphere,
the transition region and the corona. Many suggestions have
been made on the nature
of this mass cycle, from handwaving arguments to 3D MHD
models. However, each of
these suggestions has its problems and it is unclear what
really governs the mass
exchange. For example the transition region emission in...
Tanmoy Samanta
(Indian Institute of Astrophysics)
22/06/2016, 11:45
The solar chromosphere and transition region plays an important role in understanding
the interaction between the relatively cool photospheric plasma and the hot
multi-million degree corona. It is only beginning to be understood where and how the
required energy is generated, transported and dissipated. It appears that the
chromosphere and transition region plays a key role in the process....
Tiago M. D. Pereira
(University of Oslo)
22/06/2016, 12:05
Low-lying loops have been observed by IRIS at the solar limb in transition region
temperatures. It has been suggested that these loops constitute a connection between
the corona and transition region, previously known as unresolved fine structure
(UFS). In this work we make use of coordinated observations between IRIS and the
Swedish 1-m Solar Telescope to study these low-lying loops. We...
Pia Zacharias
(University of Oslo)
22/06/2016, 12:25
Observations of solar transition region emission lines reveal the presence of
redshifts up to temperatures of about 300,000 K and blueshifts for higher
temperatures. The apparent large downward flows in the lower transition region would
lead to an emptying of the corona, in contrast to what is being observed, thus some
mechanism must be responsible for maintaining the mass balance between...