Dust and magnetic fields are ubiquitous in the universe. Interstellar dust is the seeds of star and planet formation, while magnetic fields play an important role in many astrophysical phenomena, including star formation, cosmic ray transport, and synchrotron emission. The alignment of non-spherical dust grains with magnetic fields, resulting in dust polarization, provides a powerful tool to map magnetic fields. Dust polarization has been successfully used to trace magnetic fields in various scales, from ~ kpc to ~ 1000 AU scales. Recent polarization observations at mm-cm wavelengths from disks (~ 100 AU scales) by ALMA reveal that dust polarization may not trace magnetic fields, but grain growth and planetesimal formation. At the same time, polarized dust emission is considered the most critical challenge for understanding how the universe was born through so-called B-modes polarization. Therefore, accurate modeling of dust foreground polarization, which depends on dust astrophysics, gas density, and magnetic field structure, is required for the B-modes detection. The aim of this workshop is to bring together local and international experts in dust astrophysics and magnetic fields in order to discuss the following important aspects:
1. Dust Properties and Dust Evolution from Angstroms to centimeters to planetesimals
2. Physics of Dust Polarization: grain alignment, scattering, and observational tests
3. What is the role of magnetic fields on star and planet formation?
4. What can we learn from mm-cm dust polarization observations in the ALMA era: Magnetic fields or Grain Growth?
5. Alternative ways to trace magnetic fields as a synergy to dust polarization
6. Related important issues: turbulence, filaments, and shocks
7. What dust astrophysics and magnetic fields required for accurate modeling of Galactic foreground for CMB B-modes detection?
▶ Conference Website: http://coma.kasi.re.kr/cosdm2018
■ Speaker : Dr. Dae Jung Yu (Kyung Hee University)
■ Title : Some aspects of MHD waves in the solar atmosphere
■ Abstract :
It is now well-recognized that MHD waves are ubiquitous in the sun's atmosphere. The contribution of MHD waves to the unusual coronal temperature is considered to be important and their characteristics are crucial to infer the physical parameters like e.q. magneitc field, density, and so son, leading to the coronal seismology. Some basic properties of MHD waves in homogeneous and inhomogeneous plasmas are addressed. When a plasma medium has an inhomogeneity, two different MHD waves may couple to one another and exchange energies. This process leads to mode conversion or resonant absorption, which is believed to be crucial for the rapid damping of MHD waves and coronal heating. I introduce resonant absorption briefly and then explain how it has been used as a tool for the coronal seismology, which is followed by my recent work on the effect of coronal loop motion on the loop oscillations. Some speculations for future researches are presented at the end.
■ Time/Place : Thursday, May 31, 2018, 04:00 pm at room #309, Sejong Hall, KASI
■ Host : Jungjoon Seough
한(KASI, ROKAF)-미(AFRL, JHUAPL)-일(Nagoya Univ., NICT) 중위도 전리권 불균일 현상 협력연구 워크숍