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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 2019/03/21 - 5/30  Seminar Room #1323  Dr. Hyangtag Lim (KIST) and etc.  Spring 2019: Physics Seminar Serises
공지 2019/02/25 - 06/03  Seminar Room 1501  양용수 교수 (Prof. Yongsoo Yang, KAIST) and etc.  Spring 2019: Physics Colloquium
170 Apr. 19 (Fri.), 02:30 PM  E6-2. 1st fl. #1323  Dr. YoungWoo Nam  A family of finite-temperature electronic phase transitions in graphene multilayers file
169 Apr. 5 (Tue.), 4PM  E6-2. 1st fl. #1322  Dr. Ara Go, Columbia University  A new impurity solver for multi-orbital systems: adaptive truncation of the Hilbert space
168 2015/09/07, 3PM  E6-2. 1st fl. #1318  Dr. Jasbinder Sanghera (U.S. Naval Research Laboratory (NRL))  Advanced Optical Materials and Devices at NRL
167 4pm, Sep. 21 (Wed.  E6-2. #2502(2nd fl.)  Dr. Henrik Johannesson , University of Gothenburg (Sweden) and Beijing Computational Science Research Center (China)  Entanglement probe of two-impurity Kondo physics
166 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?
165 May 11 (Wed.), 4 PM  E6-2. #1323(1st fl.)  Dr. Bumjoon Kim, Max Planck Institute for Solid State Research  The quest for novel high-temperature superconductors---Prospects and progress in iridates
164 May 24 (Tue) 4 PM  E6-2. #1323(1st fl.)  Dr. Euyheon Hwang, SKKU Advanced Institute of Nanotechnology, Sung Kyung Kwan University  Electronic and magnetic properties of 2D transition-metal thiophosphates and tunability of magnetic order with carrier density
163 Oct. 07 (Fri), 1:30 PM  E6-2. #1323(1st fl.)  Dr. Suk Bum Chung, IBS-CCES , Seoul National University  “Symmetry and topology in transition metal dichalcogenide?”
162 Oct. 07 (Fri), 4:00 PM  E6-2. #1323(1st fl.)  Dr. Choong Hyun Kim,IBS-CCES, Seoul National University  “Tilt engineering of 4d and 5d transition metal oxides?”
161 Nov. 04 (Fri), 1:30 PM  E6-2. #1323(1st fl.)  Dr. Jonghyun Song, Department of Physics, Chungnam National University  Exotic phenomena at oxide LaAlO3/SrTiO3 hetero-interface and their applications
160 Nov. 04 (Fri), 3:00 PM  E6-2. #1323(1st fl.)  Dr. Dohun Kim, Department of Physics and Astronomy, SNU  Quantum information experiments using few electron spins in semiconductors
159 Nov. 10th(Thu) 4 p.m.  E6-2. #1323(1st fl.)  Prof. Min Seok Jang, Electrical Engineering, KAIST  Low Dimensional Active Plasmonics and Electron Optics in Graphene
158 2015/07/15, 2PM  E6-2,1323  Dr. Se Young Park(Rutgers Univ.)  Electronic and optical properties of titanate-based oxide superlattices
157 April 6, 2016 (Wed), 3:30 PM  E6-2, RM #1323  Dr. Andrei Matlashov (Los Alamos National Laboratory)  Superconducting Quantum Interference Devices for Precision Detection
156 Dec. 15 (Fri.), 9:20 AM  E6-2, Lecture Room #1323  Prof. Jhinhwan Lee 외 9명  Workshop on Magnetism in Unconventional Superconductors 개최 file
155 2015/10/15, 10AM  E6-2, 5th fl. #5318  Dr. Mark D. Bird (Florida State University)  Development of Large-Bore, High Field Magnets at the NHMFL
154 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
153 June 14 (THU), 10:00 AM  E6-2, 2nd fl. #2502  Prof. Kenji Toyoda  Phonons and polariton-like particles in trapped ions for quantum computation and quantum simulation file
152 Jul 3rd, 2019 (Wed)  E6-2, 2501  Kyung Soo Choi  Many-body quantum electrodynamis (QED) with atoms and photons: A new platform for quantum optics" file
151 2016/03/11-06/09  E6-2, 1501 외  박권(KAIS) 외  Physics Seminar Serises : 2016 Spring file