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장소 #1323(E6-2 1st fl.) 
일시 Jun 1 (Wed) 4 PM 
연사 Kil-Byoung Chai, Caltech 

Laboratory experiments relevant to mesospheric clouds, Saturn’s rings & astrophysical jets

 

Jun 1 (Wed) 4 PM, #1323(E6-2 1st fl.)
Kil-Byoung Chai, Caltech

 

An rf discharge with liquid nitrogen cooled electrodes and injected water vapor has been used to study nucleation, growth, and dynamics of water-ice grains spontaneously formed in a plasma environment. Examples of water-ice dusty plasmas include polar mesospheric clouds, Saturn’s diffusive rings, and protoplanetary disks. We found that fast grain growth to nonspherical shape with up to 5:1 elongation occurs when the water molecule mean free path exceeds the ice grain screening length. Ice grains grow largest in light gas plasmas, up to 500 µm long in hydrogen plasma. Elongated ice grains align along the plasma ambipolar electric field. Microscope images reveal that the ice grains have fractal nature with 1.7 typical fractal dimension. After the growth process ends, poloidal vortex motion of ice grains is observed and is shown to result from the non-conservative ion drag force.

The Caltech jet experiment produces low beta, high Lundquist number, high density (~1022 m-3) MHD-driven plasma jets and so is similar to astrophysical jets and solar corona loops. We have recently studied various phenomena associated with magnetic reconnection induced by a kink-driven Rayleigh-Taylor instability using comprehensive diagnostics. The results of this study include the following: A spatially localized EUV burst is imaged at the presumed position of fast magnetic reconnection in a plasma jet; the existence of this localized EUV burst indicates strong localized electron heating. Circularly polarized high frequency whistler waves are simultaneously observed indicating that Hall dynamics likely governs the reconnection. Spectroscopic measurement shows simultaneous fast ion heating. We propose that the electron heating is consistent with Ohmic dissipation while the ion heating is consistent with ion trajectories becoming stochastic.

 

번호 일시 장소 연사 제목
공지 2019/09/18 - 12/5  Seminar Room #1323  Prof. David Schuster and etc.  Fall 2019: Physics Seminar Serises
공지 2019/09/02 - 12/09  Seminar Room 1501  이호성 박사 (한국표준과학연구원) and etc.  Fall 2019: Physics Colloquium
182 Feb. 1 (Wed.), 2p.m.  #1323(E6-2. 1st fl.)  Dr. Michihisa Yamamoto, Department of Applied Physics, The University of Tokyo  Quantum electron optics using flying electrons
181 Sep. 10 (Tue.), 03:00 PM  E6-2. 1st fl. #1323  Dr. Mikhail Kiselev  Two-Stage Kondo Effect file
180 Nov. 3 (Fri.), 2:30 PM  #1323 (1st fl., E6-2.)  Dr. MinChul Lee(Department of Applied Physics, Kyung Hee Univ.)  Quantum Resistor-Capacitor Circuit with Majorana Edge States file
179 July 30 (Tue), 4:00 PM  #1323, E6-2  Dr. Mingu Kang  Dirac fermions and flat bands in correlated kagome metals file
178 Apr. 28 (Fri.), 04:00 PM  #1323 (E6-2. 1st fl.)  Dr. Minkyung Jung Research Institute, DGIST  Carbon nanotubes coupled to superconducting impedance matching circuits
177 Sep. 29 (Thu), 4:00 PM  E6-2. #2501(2nd fl.)  Dr. Minu Kim, Institute for Basic Science, Seoul National University  Exploring the phase diagram of BaBiO3: epic voyage of just another bad trip?
176 3 PM, 12 Jun (Wed), 2019  Rm# 1323, E6-2  Dr. Minyoung You  The relation between free and interacting fermionic SPT phases file
175 April 26 (Tue), 4PM  #1323(1st Floor. E6-2)  Dr. Myung-Ho Bae, Korea Research Institute of Standards and Science  Transport spectroscopy for electronic bands in carbon-based nanomaterials with weak-bond contacts
174 May. 11 (Fri.), 04:00 PM  E6-2. 1st fl. #1323  Dr. Nam Kim  암페어 단위 재정의와 단전자 펌프 소자 개발 file
173 Jun. 1(Wed) 10:30 AM  BK21 Conference Room (#1318, E6-2)  Dr. Noriaki Horiuchi, Editor, Nature Photonics  Welcome to Nature Photonics
172 July 2. 2018 (Monday) 3:00 PM  Seminar Room (C303), Creation Hall (3F), KAIST Munji Campus  Dr. Peter Winter (Argonne National Laboratory)  High Precision Magnetic Field Measurement for the Muon g-2 Experiment file
171 2015/10/16, 3PM  E6-2, 5th fl. #5318  Dr. Pierre Pugnat , (CNRS-LNCMI)  High Magnetic Fields to Probe the sub-eV range of Particle/Astroparticle Physics - From the OSQAR experiments at CERN up to new perspectives at LNCMI-Grenoble
170 Nov. 9 (Fri.), 02:30 PM  E6-2. 1st fl. #1323  Dr. Pilkyung Moon  Moiré superlattices – from twisted bilayer graphene to quasicrystal file
169 Jun. 2 (Fri.), 4:00 PM  #1323 (E6-2. 1st fl.)  Dr. Sang Wook Kim  Maxwell's demon in quantum wonderland file
168 2015/12/03, 4PM  E6-2, #1323  Dr. Sang-Yun Lee (3rd institute of Physics, University of Stuttgart, Germany)  Hybrid solid state spin qubits in wide bandgap semiconductors
167 Mar. 24 (Fri.), 4:00 PM  #1323 (1st fl. E6-2)  Dr. SangWook Lee  Graphene based nano electronics and nano electromechanics; focusing on precise control of nano structures for studying accurate physical properties
166 Sep. 29th(Thu), 4PM  E6-2 #1323 (1st floor)  Dr. Sangyoon Han, Department of Physics, KAIST  Large-scale Silicon Photonic MEMS Switches
165 2015/07/15, 2PM  E6-2,1323  Dr. Se Young Park(Rutgers Univ.)  Electronic and optical properties of titanate-based oxide superlattices
164 June 17 (Mon.), 10:30 AM  #1323, E6-2  Dr. See-Hun Yang  Chiral Spintronics file
163 Apr. 19 (Fri.), 04:00 PM  E6-2. 1st fl. #1323  Dr. Seok Kyun Son  Graphene and hBN heterostructures file