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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
158 Jan.28(Thu), 06:00PM  Online Seminar  Alexandre Zagoskin(Loughborough Univ.)  Quantum metamaterials: concept, theory, prototypes and possible applications file
157 Jan.28(Thu), 03:00PM  Zoom  Yaroslav Tserkovnyak (UCLA)  Topological Transport of Deconfined Hedgehogs in Magnets file
156 JAN. 7 (Mon), 03:00 PM  E6-2. 2st fl. #2501  Dr. Byoung min Kang  Many-Body Invariants for Multipoles in Higher-Order Topological Insulators file
155 February 21 (Thu.), 16:00 PM  #5313, E6-2  Prof. Diptimoy Ghosh  B-meson charged current anomalies - Theoretical status file
154 February 20 (Thu), 4:00 PM  #1323, E6-2  Seunghyun Khim  Unconventional superconductivity in the locally non-centrosymmetric heavy-fermion CeRh2As2 file
153 February 13th (Thur.), 16:30 PM  E6-6, #119  Dr. Seyoon Kim(University of Wisconsin-Madison)  Enhanced Light-Matter Interactions in Graphene with Noble Metal Plasmonic Structures file
152 February 12(Web.)  E6-2, #5318  Prof. Kunio Kaneta  From inflation to new weak-scale file
151 Feb.17(Wed)~19(Fri), 09:00~11:00AM  Online  Prof. Subir Sachdev (Harvard University)  석학 대중 강연 및 강의 시리즈 file
150 Feb.15(Mon), 05:00PM  Zoom  Yoshichika Otani(Tokyo Univ.)  Magnetic Cluster Octupole Domain evolutation in chiral antiferromagnets file
149 Feb. 25 - Jun 3  Rm. 1501 (E6)    Spring 2019: Physics Colloquium file
148 Feb. 2(Tue) 2:30 PM  Zoom  Prof. Sangsik Kim (Texas Tech University, USA)  Quantum- & Nano-Photonics 세미나(Integrated Nanophotonics with Metamaterials, Microcomb, and Atomic Systems) file
147 Feb. 12 (Mon), 3:00pm  #C303, (Creation Hall 3F, KAIST Munji Campus)  Dr. Byeongsu Yang, Kamioka Observatory, Univ. of Tokyo  The recent result of XMASS Experiment
146 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
145 December 5 (Thu.), 16:00 PM  #1323, E6-2  Prof. Soon-Hong Kwon  Subwavelenth Photonic Devices: From Single Photon Sources to Solar Cell file
144 December 3 (Tue.), 4:00 PM  #1323, E6-2  Dr. Jong Mok Ok  Toward Quantum Materials with Correlated Oxides file
143 December 27(Fri.), 15:00  E6-2,#5318  Han Gyeol Suh  The superconducting order parameter puzzle of Sr2RuO4 file
142 December 2(Wed), 10:00AM  Zoom  Prof. Rakshya Katiwada (Illinois Institute of Technology)  Recent progress in Axion Dark Matter eXperiment (ADMX) technology file
141 December 18 (Tue.), 4:00 PM  #1323, E6-2  Prof. Shin-ichi Uchida  Road to Higher Tc Superconductivity file
140 December 13 (Fri.), 1:30-4:30 PM  #1323, E6-2    Biophysics Mini-symposium at KAIST file
139 December 13 (Fri.), 1:00 PM  #2501, E6-2  Dr. Chang-Jong Kang  Computational Material Designs: Current Status and Future Directions file