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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
130 Jun. 2 (Fri.), 4:00 PM  #1323 (E6-2. 1st fl.)  Dr. Sang Wook Kim  Maxwell's demon in quantum wonderland file
129 May. 12 (Fri.), 01:30 PM  E6-2. 1st fl. #1323  Dr. Young Kuk Kim  Topological Dirac insulator
128 Apr. 27, 2017 (Thu) 4:00 pm  Seminar Room(#1323, E6-2)  Prof.Donghan Lee (Chungnam National Univ.)  반도체 양자점을 이용한 단광자 광원
127 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
126 Apr. 28 (Fri.), 02:30 PM  E6-2. 1st fl. #1323  Dr. JeongYoung Park Graduate School of EEWS, KAIST  Hot electron generation at surfaces and its impact to catalysis and renewable energy conversion
125 April 6, 2017 (Thu), 4:00 pm  IBS CAPP seminar room, Creation Hall (3F), KAIST Munji Campus  Prof. Youngjoon Kwon (Yonsei University)  For whom the Belle tolls
124 April 5th 2017, 12:00 ~ 13:00  Room 101, Creative Learning Bldg.(E11)  Prof. Wonho Choe(Dept. of Physics),Prof. Young-chul GHIM(Dept. of Nuclear & Quantum Engineering)  2017년 4월 첫수 융합포럼 개최 안내(물리학과 & 원자력 및 양자공학과 공동 개최)/The First Wednesday Multidisciplinary Forum in April 2017 organized by Dept. of Physics & Dept. of Nuclear & Quantum Engineering file
123 2017/03/06 - 05/29  Seminar Room 1501  이종봉 박사 (POSTECH) 외  Spring 2017: Physics Colloquium file
122 2017/03/21 - 06/08  Seminar Room 1323  조길영 박사(KAIST) 외  Spring 2017: Physics Seminar Serises file
121 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
120 Mar. 24 (Fri.), 2:30 PM  #1323 (1st fl. E6-2).  Dr. MahnSoo Choi  Topological Dynamics
119 Mar. 2nd (Thu), 4:00 p.m  #1323(E6-2. 1st fl.)  Dr. Jonathan Denlinger, Lawrence Berkeley National Lab  “Progress in the comparison of ARPES to DMFT for d and f strongly correlated electron systems”
118 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
117 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
116 Dec. 12th (Mon)  1:30p.m. #1323(E6-2. 1st fl.)  Dongjoon Song , AIST  “Possible symmetry in the phase diagrams of electron- & hole-doped cuprate high-Tc superconductors”
115 Dec. 9(Fri), 1:30 p.m.  #1323(E6-2. 1st fl.)  Dr. Jae Yoon Cho, POSTECH  Entanglement area law in strongly-correlated systems
114 Dec. 9(Fri), 4p.m.  #1323(E6-2. 1st fl.  Dr. Kun Woo Kim, KIAS  Shift Charge and Spin Photocurrents in Dirac Surface States of Topological Insulator
113 Dec. 8(Thu) 4p.m.  #1323(E6-2. 1st fl.)  Dr. Jinhyoung Lee, Hanyang University  Dynamical Resonance between Two Optical Cavities via Optomechanical Oscillator
112 Nov. 29(Tue) 4p.m.  #1323(E6-2. 1st fl.)  Dr. SungBin Lee, KAIST  Symmetry Protected Kondo Metals and Their Phase Transitions
111 Nov. 24(Thu) 4p.m.  #1323(E6-2. 1st fl.)  Dr. Jai-Min Choi, Chonbuk National Univiersity  Harmonic oscillator physics with single atoms in a state-selective optical potential