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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
75 Nov. 9 (Fri.), 02:30 PM  E6-2. 1st fl. #1323  Dr. Pilkyung Moon  Moiré superlattices – from twisted bilayer graphene to quasicrystal file
74 Nov. 9 (Fri.), 04:00 PM  E6-2. 1st fl. #1323  Dr. Donghun Lee  Quantum sensing and imaging with diamond defect centers for nano-scale spin physics file
73 Dec. 7 (Fri.), 02:30 PM  E6-2. 1st fl. #1323  Dr. Gyung Min Choi  Spin generation from heat and light in metals file
72 Dec. 7 (Fri.), 04:00 PM  E6-2. 1st fl. #1323  Dr. Joon Ho Jang  Novel probes of interacting electrons in 2D systems file
71 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
70 DEC. 16~18 (Sun~Tue)  E6-2. 1st fl. #1323  Prof. Keisuke Totsuka  Lectures on 2d Conformal Field Theory file
69 Dec. 26 (Wed.), 04:00 PM  E6-2. 1st fl. #1323  Dr. Isaac H. Kim  Brane-like defect in 3D toric code file
68 DEC. 27 (Thu), 04:00 PM  E6-2. 1st fl. #1323  Prof. Na Young Kim  Quantum Innovation (QuIN) Laboratory file
67 Mar. 29 (Fri.), 02:30 PM  E6-2. 1st fl. #1323  Dr. Seung Hyub Baek  Epitaxial Multifunctional Oxide Thin Films for Novel Electronics file
66 Mar. 29 (Fri.), 04:00 PM  E6-2. 1st fl. #1323  Dr. Taeyoung Choi  Coherent Quantum Control and Magnetism on atoms – Trapped ion and ESR STM file
65 Apr. 19 (Fri.), 04:00 PM  E6-2. 1st fl. #1323  Dr. Seok Kyun Son  Graphene and hBN heterostructures file
64 Apr. 19 (Fri.), 02:30 PM  E6-2. 1st fl. #1323  Dr. YoungWoo Nam  A family of finite-temperature electronic phase transitions in graphene multilayers file
63 Sep. 10 (Tue.), 03:00 PM  E6-2. 1st fl. #1323  Dr. Mikhail Kiselev  Two-Stage Kondo Effect file
62 Sep. 27 (Fri.), 04:00 PM  E6-2. 1st fl. #1323  Dr. Jindong Song  0D/1D/2D/3D III-V materials grown by MBE for Optelectronics file
61 Sep. 27 (Fri.), 02:30 PM  E6-2. 1st fl. #1323  Dr. Joon Sue Lee  Spin-charge conversion in topological insulators for spintronic applications file
60 Nov. 1 (Fri.), 02:30 PM  E6-2. 1st fl. #1323  Dr. YoungWook Kim  Squeezing the best out of 2D materials file
59 Nov. 1 (Fri.), 04:00 PM  E6-2. 1st fl. #1323  Dr. Ju-Jin Kim  Electron transport through weak-bonded contact metal with low dimensional nano-material file
58 2016/03/11 1:30 PM  E6-2. 1st fl. #1501  Dr. Kwon Park  Topological phases of matter in nonequilibrium: Topology of the Wannier-Stark ladder
57 2016/03/11 4 PM  E6-2. 1st fl. #1501  Dr. Tae-Hwan KIM (POSTECH)  Jan. Switching handedness of of chiral solitons in Z4 topological insulators
56 Apr. 01 (Fri.) 2:30 PM  E6-2. 1st fl. #1501  Dr. KICHEON KANG, Chonnam National University  Interference of single charged particles without a loop and dynamic nonlocality