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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
150 Feb.17(Wed)~19(Fri), 09:00~11:00AM  Online  Prof. Subir Sachdev (Harvard University)  석학 대중 강연 및 강의 시리즈 file
149 Feb.15(Mon), 05:00PM  Zoom  Yoshichika Otani(Tokyo Univ.)  Magnetic Cluster Octupole Domain evolutation in chiral antiferromagnets file
148 Feb. 25 - Jun 3  Rm. 1501 (E6)    Spring 2019: Physics Colloquium file
147 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
146 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
145 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
144 December 5 (Thu.), 16:00 PM  #1323, E6-2  Prof. Soon-Hong Kwon  Subwavelenth Photonic Devices: From Single Photon Sources to Solar Cell file
143 December 3 (Tue.), 4:00 PM  #1323, E6-2  Dr. Jong Mok Ok  Toward Quantum Materials with Correlated Oxides file
142 December 27(Fri.), 15:00  E6-2,#5318  Han Gyeol Suh  The superconducting order parameter puzzle of Sr2RuO4 file
141 December 2(Wed), 10:00AM  Zoom  Prof. Rakshya Katiwada (Illinois Institute of Technology)  Recent progress in Axion Dark Matter eXperiment (ADMX) technology file
140 December 18 (Tue.), 4:00 PM  #1323, E6-2  Prof. Shin-ichi Uchida  Road to Higher Tc Superconductivity file
139 December 13 (Fri.), 1:30-4:30 PM  #1323, E6-2    Biophysics Mini-symposium at KAIST file
138 December 13 (Fri.), 1:00 PM  #2501, E6-2  Dr. Chang-Jong Kang  Computational Material Designs: Current Status and Future Directions file
137 Dec.9(Wed), 10:00AM  Zoom  Prof. Andrew Geraci (Northwestern University)  Searching for the QCD axion with the ARIADNE experiment file
136 Dec.23(Wed), 10:00~16:00  Online  Prof. YongKeun Park (KAIST) and etc.  Online workshop for Quantitative Phase Imaging file
135 Dec.10(Thu), 01:55 PM  Zoom  Yin Wen (University of Tokyo)  Consistency of Boltzmann equation and light dark matter from inflaton decay
134 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
133 Dec. 9(Fri), 1:30 p.m.  #1323(E6-2. 1st fl.)  Dr. Jae Yoon Cho, POSTECH  Entanglement area law in strongly-correlated systems
132 Dec. 8(Thu) 4p.m.  #1323(E6-2. 1st fl.)  Dr. Jinhyoung Lee, Hanyang University  Dynamical Resonance between Two Optical Cavities via Optomechanical Oscillator
131 Dec. 7 (Fri.), 04:00 PM  E6-2. 1st fl. #1323  Dr. Joon Ho Jang  Novel probes of interacting electrons in 2D systems file