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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
123 April 13 (Fri.), 10am  #1323 (E6-2, 1st fl.)  Dr. Sungkun Hong  Quantum meets Mechanics: from Quantum Information to Fundamental Research file
122 Nov. 3 (Fri.), 4:00 PM  #1323 (1st fl., E6-2.)  Dr. SungDae Ji (Max Planck POSTECH/Hshinchu Center (MPK))  Expedition to the Kitaev Quantum Spin Liquid: Hunting for Majorana fermions file
121 Nov. 29(Tue) 4p.m.  #1323(E6-2. 1st fl.)  Dr. SungBin Lee, KAIST  Symmetry Protected Kondo Metals and Their Phase Transitions
120 Oct. 07 (Fri), 1:30 PM  E6-2. #1323(1st fl.)  Dr. Suk Bum Chung, IBS-CCES , Seoul National University  “Symmetry and topology in transition metal dichalcogenide?”
119 April 26 (Fri.), 4:00 PM  #1323, E6-2  Dr. Soonwon Choi  Robust Quantum Metrology using Strongly Interacting Spin Ensembles and Quantum Convolutional Neural Network file
118 Apr. 09 (Mon.), 11:00 AM  E6-2. 1st fl. #1323  Dr. Seung-Sup B. Lee  Doublon-holon origin of the subpeaks at the Hubbard band edges file
117 Jun. 01 (Fri.), 11:00 AM  E6-2. 1st fl. #1323  Dr. Seung Sae Hong  Topological phases in low-dimensional quantum materials file
116 Mar. 29 (Fri.), 02:30 PM  E6-2. 1st fl. #1323  Dr. Seung Hyub Baek  Epitaxial Multifunctional Oxide Thin Films for Novel Electronics file
115 2016/1/26, 2PM  E6-2, #1323  Dr. Sergei V. Kalinin (Center for Nanophase Materials Sciences, Oak Ridge National Laboratory)  Electrochemistry on Nano- and Atomic Levels: Scanning Probe Microscopy Meets Deep Data
114 Apr. 19 (Fri.), 04:00 PM  E6-2. 1st fl. #1323  Dr. Seok Kyun Son  Graphene and hBN heterostructures file
113 June 17 (Mon.), 10:30 AM  #1323, E6-2  Dr. See-Hun Yang  Chiral Spintronics file
112 2015/07/15, 2PM  E6-2,1323  Dr. Se Young Park(Rutgers Univ.)  Electronic and optical properties of titanate-based oxide superlattices
111 Sep. 29th(Thu), 4PM  E6-2 #1323 (1st floor)  Dr. Sangyoon Han, Department of Physics, KAIST  Large-scale Silicon Photonic MEMS Switches
110 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
109 2015/12/03, 4PM  E6-2, #1323  Dr. Sang-Yun Lee (3rd institute of Physics, University of Stuttgart, Germany)  Hybrid solid state spin qubits in wide bandgap semiconductors
108 Jun. 2 (Fri.), 4:00 PM  #1323 (E6-2. 1st fl.)  Dr. Sang Wook Kim  Maxwell's demon in quantum wonderland file
107 Nov. 9 (Fri.), 02:30 PM  E6-2. 1st fl. #1323  Dr. Pilkyung Moon  Moiré superlattices – from twisted bilayer graphene to quasicrystal file
106 2015/10/16, 3PM  E6-2, 5th fl. #5318  Dr. Pierre Pugnat , (CNRS-LNCMI)  High Magnetic Fields to Probe the sub-eV range of Particle/Astroparticle Physics - From the OSQAR experiments at CERN up to new perspectives at LNCMI-Grenoble
105 July 2. 2018 (Monday) 3:00 PM  Seminar Room (C303), Creation Hall (3F), KAIST Munji Campus  Dr. Peter Winter (Argonne National Laboratory)  High Precision Magnetic Field Measurement for the Muon g-2 Experiment file
104 Jun. 1(Wed) 10:30 AM  BK21 Conference Room (#1318, E6-2)  Dr. Noriaki Horiuchi, Editor, Nature Photonics  Welcome to Nature Photonics