Letters of Intent received in 2017

LoI 2019-1979
The magnetic Sun: Showcasing fundamental physical processes in the Universe

Date: 24 September 2019 to 27 September 2019
Category: Non-GA Symposium
Location: Tokyo, Japan
Contact: Toshifumi Shimizu (shimizu@solar.isas.jaxa.jp)
Coordinating division: Division E Sun and Heliosphere
Other divisions: Division B Facilities, Technologies and Data Science
Division D High Energy Phenomena and Fundamental Physics
Division G Stars and Stellar Physics
Co-Chairs of SOC: Takashi Sakurai (National Astronomical Observatory of Japan)
Takaaki Yokoyama (The University of Tokyo)
Co-Chairs of LOC: Toshifumi Shimizu (ISAS/JAXA)
Yukio Katsukawa (National Astronomical Observatory of Japan)
Taro Sakao (ISAS/JAXA)



magnetic reconnection
MHD waves and energy transport
MHD instabilities developing into explosive phenomena
dynamo to generate magnetic fields of various scales
Dissipation of magnetic energy and the heating of the atmosphere
solar and stellar winds
dynamics in the corona and chromosphere
future facilities and international collaboration



The solar atmosphere is filled with various types of heating and dynamical phenomena, including explosive flares and jets, which are created by fundamental physical mechanisms associated with magnetic fields. They include the dynamo mechanism for the creation of magnetic fields, magneto-convection and MHD waves for transporting the energy via magnetic fields, MHD instabilities resulting in large-scale explosions, and magnetic reconnection for transient dissipation of magnetic energy. All of them are physical mechanisms that should work in various kinds of astronomical objects, including stellar atmospheres, galaxies and inter-galactic media, and black holes. Recent space-borne observations by Hinode, SDO, and IRIS have been providing high spatial resolution observations of dynamics in the solar photosphere, chromosphere and corona, and solar researchers are actively working to improve our understanding of functions of these physical mechanisms operating on the Sun. MHD numerical studies have also been extensively advanced to interpret these observations in terms of fundamental physics laws and to present the latest description of solar phenomena governed by fundamental physical mechanisms.
The primary objectives of the proposed symposium are not restricted to the Sun; Rather, theoretical and observational astrophysicists, experimental plasma physicists and space plasma physicists who are interested in the fundamental physical mechanisms mentioned earlier are encouraged to participate in the symposium, so that the symposium can provide a unique opportunity to discuss physical mechanisms comprehensively from various viewpoints, which may develop new interdisciplinary approaches for understanding our universe in the international research community of astronomy and related fields.
The proposed symposium for focusing on the magnetic Sun and fundamental physical mechanisms acting in the magnetic Sun is timely, because new advanced facilities are starting their observations in the coming years. The 4-m aperture DKIST will have the first light in 2019, opening a new research era about the solar chromosphere with super high spatial resolution imaging and spectro-polarimetric observations. Moreover, in 2018-2019, the Parker Solar Probe and the Solar Orbiter will be launched to approach the Sun and explore the heating of the corona and the acceleration of the solar wind, by coordinating in-situ measurements and remote-sensing observations. These observational efforts would enable researchers to investigate fundamental mechanisms working there more deeply. Before starting new observations, it is important to update our current status by reviewing recent observations by Hinode, SDO, IRIS and all other observatories and to have stimulated discussions on the directions of researches.
Across their large portion of the parameter space, the stars have hot atmospheres and show mass loss. Therefore our new knowledge on the coronal heating and solar wind acceleration would be helpful in investigating stellar winds and hot plasmas in the universe. The proposed symposium will provide a unique and timely opportunity for interaction between solar-physics-based researchers and astrophysics-based researchers.