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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.

 

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260 Dec. 26 (Wed.), 04:00 PM  E6-2. 1st fl. #1323  Dr. Isaac H. Kim  Brane-like defect in 3D toric code file
259 DEC. 27 (Thu), 04:00 PM  E6-2. 1st fl. #1323  Prof. Na Young Kim  Quantum Innovation (QuIN) Laboratory file
258 Dec. 3 (Fri.), 02:30 PM  Zoom webinar  Dr. Soong-Geun Je(Chonnam National University)  Topological Spin Textures: Skyrmions and Beyond file
257 Dec. 3 (Fri.), 04:00 PM  Zoom webinar  Dr. Hyejin Jang (Seoul National University)  Nonequilibrium Heat Transport in Elemental Metals Probed by an Ultrathin Magnetic Thermometer file
256 Dec. 7 (Fri.), 02:30 PM  E6-2. 1st fl. #1323  Dr. Gyung Min Choi  Spin generation from heat and light in metals file
255 Dec. 7 (Fri.), 04:00 PM  E6-2. 1st fl. #1323  Dr. Joon Ho Jang  Novel probes of interacting electrons in 2D systems file
254 Dec. 8(Thu) 4p.m.  #1323(E6-2. 1st fl.)  Dr. Jinhyoung Lee, Hanyang University  Dynamical Resonance between Two Optical Cavities via Optomechanical Oscillator
253 Dec. 9 (Fri), 11:00AM  E6-2 #1323  김도헌(서울대 물리천문학부 교수)  (응집물리 세미나) Single-shot measurements of strongly-correlated artificial molecular levels in semiconductor quantum dots
252 Dec. 9(Fri), 1:30 p.m.  #1323(E6-2. 1st fl.)  Dr. Jae Yoon Cho, POSTECH  Entanglement area law in strongly-correlated systems
251 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
250 Dec.10(Thu), 01:55 PM  Zoom  Yin Wen (University of Tokyo)  Consistency of Boltzmann equation and light dark matter from inflaton decay
249 Dec.23(Wed), 10:00~16:00  Online  Prof. YongKeun Park (KAIST) and etc.  Online workshop for Quantitative Phase Imaging file
248 Dec.9(Wed), 10:00AM  Zoom  Prof. Andrew Geraci (Northwestern University)  Searching for the QCD axion with the ARIADNE experiment file
247 December 13 (Fri.), 1:00 PM  #2501, E6-2  Dr. Chang-Jong Kang  Computational Material Designs: Current Status and Future Directions file
246 December 13 (Fri.), 1:30-4:30 PM  #1323, E6-2    Biophysics Mini-symposium at KAIST file
245 December 18 (Tue.), 4:00 PM  #1323, E6-2  Prof. Shin-ichi Uchida  Road to Higher Tc Superconductivity file
244 December 2(Wed), 10:00AM  Zoom  Prof. Rakshya Katiwada (Illinois Institute of Technology)  Recent progress in Axion Dark Matter eXperiment (ADMX) technology file
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