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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
202 October 29 (Tue.), 14:30 PM  #1323, E6-2  Prof. Jörg Wrachtrup  Quantum sensing file
201 May 2 (Thu.), 4:00 PM  #1323, E6-2  Prof. Joon Ik Jang  Anomalous optical properties of halide perovskites file
200 April 11 (Thu.), 16:00 PM  #1323, E6-2  Prof. Joo-Hyoung Lee, GIST  Massive screening for cathode active materials using deep neural network file
199 September 20 (Thu.), 16:00  #1323, E6-2  Prof. Joo-Hiuk Son  Toward Cancer Treatment Using Terahertz Radiation: Demethylation of Cancer DNA file
198 October 18 (Thu.), 16:00 PM  #1323, E6-2  Prof. Jongseok Lee  Applications of nonlinear optics for condensed matter researches file
197 May 9 (Wed.), 04:00 PM  #1323, E6-2  Prof. Jong-Soo Rhyee  Recent advances in thermoelectric bulk composites file
196 2017.1.9(Mon), 4PM  Lecture Hall, College of Natural Sciences [#1501,E6-2]  Prof. John Michael Kosterlitz, Brown University  Topological Defects and Phase Transitions" file
195 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
194 April 23 (Tue.), 4:00 PM  #1323, E6-2  Prof. Johan Chang  From Mott physics to high-temperature superconductivity file
193 November 14 (Thu.), 16:00 PM  #1323, E6-2  Prof. Ji-Hun Kang  Semi-classical model of polariton propagation file
192 Dec. 15 (Fri.), 9:20 AM  E6-2, Lecture Room #1323  Prof. Jhinhwan Lee 외 9명  Workshop on Magnetism in Unconventional Superconductors 개최 file
191 November 7 (Thu.), 16:00 PM  #1323, E6-2  Prof. Je-Hyung Kim  Integrated quantum photonics with solid-state quantum emitters file
190 May 29 (Tue.), 04:00 PM  #1323, E6-2  Prof. Jae-Won Jang  Investigation on metal nanostructure/semiconductor junction and its applications file
189 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
188 DEC. 11 (Tue), 04:00 PM  E6-2. 1st fl. #1323  Prof. Hiroshi Shinaoka  Natural compact representation of Matsubara Green’s functions: applications to analytic continuation and quantum many-body simulations file
187 AUG. 31 (Thu.), 2 PM  #5318(E6-2. 5th fl.)  Prof. Hiroaki Ishizuka (The University of Tokyo)  “Berry phase and nonlinear response: photocurrent in noncentrosymmetric insulators and Weyl semimetals” file
186 May 31 (Fri.), 11:00 AM  #1323, E6-2  Prof. Guido Burkard  Cavity QED with Spin Qubits file
185 2015/07/23,1:30PM  E4, B401  Prof. Gilles Lérondel (Univ. of Technology of Troyes)  Enhanced ZnO based UV photonics and related applications file
184 February 21 (Thu.), 16:00 PM  #5313, E6-2  Prof. Diptimoy Ghosh  B-meson charged current anomalies - Theoretical status file