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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
159 July 2, 2020 (Thursday)  Zoom Video Conference Seminar  Dr. Emmanuel Flurin (CEA Saclay)  An irreversible qubit-photon coupling for the detection of itinerant microwave photons file
158 July 13, 2018 at 14:00  Room 5318, KAIST Natural Sciences Lecture Hall(E6).  Prof. Ian Lewis (The University of Kansas, Department of Physics & Astronomy)  Loop Induced Single Top Partner Production and Decay at the LHC
157 July 10 (Wed.), 04:00 PM-  Academic Cltural Complex (E9) 5층 스카이라운지  Prof. Sidney Nagel/Young-Kee Kim  Public Lectures file
156 Jul. 28 (Thu.) 4PM  #1323(E6-2. 1st fl.)  Prof. Johannes Pollanen, Jerry Cowen Chair of Experimental Physics at Michigan State University  Low Dimensional Electrons: On the Road to Hybrid Quantum Systems
155 Jul. 08 (Fri.) 2PM  #1323(E6-2. 1st fl.)  Dr. Junhyun Lee, Harvard University  Electronic quasiparticles in the quantum dimer model
154 Jul. 08 (Fri.) 11:00 AM  #1323(E6-2. 1st fl.)  Dr. Michael Lawler(Binghampton Univ. / Cornell Univ.)  Isostatic magnetism
153 Jul. 07 (Thu.) 2PM  #1323(E6-2. 1st fl.)  Dr. Eun Ah Kim, CORNELL UNIV.  Let there be topological superconductors
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 January 23, 2019  Rm. C303, Creation Hall (3F), Munji Campus  Mikko Mottonen  Ultrasensitive Microwave Bolometer: Opportunity for Axion Detectors file
150 January 17 (Fri), 4:00 PM  #1323, E6-2  Hiroki Ikegami  Symmetry Breaking and Topology in Superfluid 3He file
149 Jan.9 (Wed.), 04:00 PM  E6-2. 2nd fl. #2501  Dr. Heung-Sik Kim  Molecular Mott state in the deficient spinel GaV4S8 file
148 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
147 February 21 (Thu.), 16:00 PM  #5313, E6-2  Prof. Diptimoy Ghosh  B-meson charged current anomalies - Theoretical status file
146 February 20 (Thu), 4:00 PM  #1323, E6-2  Seunghyun Khim  Unconventional superconductivity in the locally non-centrosymmetric heavy-fermion CeRh2As2 file
145 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
144 February 12(Web.)  E6-2, #5318  Prof. Kunio Kaneta  From inflation to new weak-scale file
143 Feb. 25 - Jun 3  Rm. 1501 (E6)    Spring 2019: Physics Colloquium file
142 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
141 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
140 December 5 (Thu.), 16:00 PM  #1323, E6-2  Prof. Soon-Hong Kwon  Subwavelenth Photonic Devices: From Single Photon Sources to Solar Cell file