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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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공지 2019/02/25 - 06/03  Seminar Room 1501  양용수 교수 (Prof. Yongsoo Yang, KAIST) and etc.  Spring 2019: Physics Colloquium
95 2016/09/29-12/13  E6-2, #1323  Sangyoon Han 외  2016 Fall, Physics Seminar Serises file
94 Sep. 29th(Thu), 4PM  E6-2 #1323 (1st floor)  Dr. Sangyoon Han, Department of Physics, KAIST  Large-scale Silicon Photonic MEMS Switches
93 Sep. 29 (Thu), 4:00 PM  E6-2. #2501(2nd fl.)  Dr. Minu Kim, Institute for Basic Science, Seoul National University  Exploring the phase diagram of BaBiO3: epic voyage of just another bad trip?
92 Sep. 22, 2016(Thu), 3:30 PM  #1323(E6-2, 1st fl.)  Dr. Haiyang Yan (Institute of Nuclear Physics and Chemistry)  Polarized 3He, Polarized Neutrons and New Interactions beyond the Standard Model
91 4pm, Sep. 21 (Wed.  E6-2. #2502(2nd fl.)  Dr. Henrik Johannesson , University of Gothenburg (Sweden) and Beijing Computational Science Research Center (China)  Entanglement probe of two-impurity Kondo physics
90 Sep. 22, 2016(Thu), 3:30 PM  #1323(E6-2, 1st fl.)  Dr. Haiyang Yan (Institute of Nuclear Physics and Chemistry)  Polarized 3He, Polarized Neutrons and New Interactions beyond the Standard Model
89 2016/09/05-12/12 4PM  Natual Scien Bldg.(E6)m #1501  Yeong Kwan Kim 외  Physics Colloquium : 2016 Fall file
88 Sep. 02(Fri) 4:00 PM  E6-2(1st fl) #1323  Dr. Yong-Joo Doh, Department of Physics and Photon Science, GIST  Quantum Electrical Transport in Topological Insulator Nanowires
87 Sep. 02(Fri) 2:30 PM  E6-2(1st fl.), #1323  Dr. Yong-Hyun Kim,Graduate School of Nanoscience and Technology, KAIST  Nanoscale Thermal Physics: Seebeck Effect and Nanoscale Friction
86 Aug. 4, 2016 (Thu.), 2:30 pm  KAIST Natural Science Building (E6-5), EDU 3.0 Room(1st fl.)  Prof. Argyris Nicolaidis  Relational Logic (with applications to Quantum Mechanics, String Theory, Cosmology, Neutrino Oscillations, Statistical Mechanics)
85 Jul. 28 (Thu.) 4PM  #1323(E6-2. 1st fl.)  Prof. Johannes Pollanen, Jerry Cowen Chair of Experimental Physics at Michigan State University  Low Dimensional Electrons: On the Road to Hybrid Quantum Systems
84 Jul. 08 (Fri.) 2PM  #1323(E6-2. 1st fl.)  Dr. Junhyun Lee, Harvard University  Electronic quasiparticles in the quantum dimer model
83 Jul. 07 (Thu.) 2PM  #1323(E6-2. 1st fl.)  Dr. Eun Ah Kim, CORNELL UNIV.  Let there be topological superconductors
82 Jul. 08 (Fri.) 11:00 AM  #1323(E6-2. 1st fl.)  Dr. Michael Lawler(Binghampton Univ. / Cornell Univ.)  Isostatic magnetism
81 Jun. 16 (Thu) 4PM  #1323(E6-2, 1st fl.)  Hyochul Kim, Samsung Advanced Institute of Technology  Quantum information processing using quantum dots and photonic crystal cavities
80 Jun. 14 (Tue) 4PM  Seminar Room (#2502, 2nd fl.)  Young-Sik Ra, Université Pierre et Marie Curie  Photonic quantum network based on multimode squeezed vacuums and single-photon subtraction
79 June 14, 2016 (Tue) 3PM  #1323 (E6-2 1st fl.)  Prof. Seungyong Hahn, Florida State University  No-Insulation High Temperature Superconductor Magnet Technology for Compact, Reliable, and Low-Cost High Field DC Magnets
» Jun 1 (Wed) 4 PM  #1323(E6-2 1st fl.)  Kil-Byoung Chai, Caltech  Laboratory experiments relevant to mesospheric clouds, Saturn’s rings & astrophysical jets
77 May 31 (Tue.) 4 PM  #1323(E6-2, 1st fl.)  Dr. Kimin Kim, KAIST  Understanding 3D tokamak physics towards advanced control of toroidal plasma
76 Jun. 1(Wed) 10:30 AM  BK21 Conference Room (#1318, E6-2)  Dr. Noriaki Horiuchi, Editor, Nature Photonics  Welcome to Nature Photonics