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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
84 June 14 (THU), 10:00 AM  E6-2, 2nd fl. #2502  Prof. Kenji Toyoda  Phonons and polariton-like particles in trapped ions for quantum computation and quantum simulation file
83 October 24 (Wed.), 10:30 AM  E6-1, Lecture Room 1501(1F)  Prof. Kerry J. Vahala  Photonic integration of next-generation clocks and Hertz-absolute-accuarcy optical frequenncy synthesizers file
82 February 12(Web.)  E6-2, #5318  Prof. Kunio Kaneta  From inflation to new weak-scale file
81 May 9 (Thu.), 16:00 PM  #1323, E6-2  Prof. Kwang Geol Lee  Quantum Optical Sensing Using Single Photons And Single Photon Emission from Single Emitters file
80 May 9 (Thu.), 16:00 PM  #1323, E6-2  Prof. Kwang Geol Lee  Quantum Optical Sensing Using Single Photons And Single Photon Emission from Single Emitters file
79 November 28 (Thu.), 16:00 PM  #1323, E6-2  Prof. Kyung Taec Kim  Generation of coherent EUV emissions using ultrashort laser pulses file
78 Apr. 19(Tue.), 2PM  #1323(E6-2. 1st fl.)  Prof. Mark Koepke, Department of Physics and Astronomy, West Virginia University, USA  Nonlocal collisional electron transport in partially ionized plasma generation, structure, and stability
77 2018년 9월 7일 (금), 3PM  학술문화관 (E9), 2층 양승택 오디토리움  Prof. Martin Head-Gordon, UC Berkeley  Recent developments in density functional theory: From new functionals to the nature of the chemical bond file
76 Nov. 10th(Thu) 4 p.m.  E6-2. #1323(1st fl.)  Prof. Min Seok Jang, Electrical Engineering, KAIST  Low Dimensional Active Plasmonics and Electron Optics in Graphene
75 2015/06/03, 12PM  Room 101, E11  Prof. Min-Kyo, Seo & Hansuek, Lee(KAIST)  The First Wednesday Multidisciplinary Forum file
74 June 4 (Tue.), 5:00 PM  #1323, E6-2  Prof. Minsu Kim  Stochastic nature of bacterial eradication using antibiotics file
73 DEC. 27 (Thu), 04:00 PM  E6-2. 1st fl. #1323  Prof. Na Young Kim  Quantum Innovation (QuIN) Laboratory file
72 October 17 (Thu.), 16:00 PM  #1323, E6-2  Prof. Namkyoo Park  Top down manipulation of Waves : From Metamaterials, Correlated Disorder, Quantum Analogy, to Digital Processing file
71 August. 14th (Wed.), 4:00PM,  Rm. 1323, E6  Prof. Nicolas Treps  Quantum Optics, at the heart of quantum metrology and quantum information file
70 Aug. 16 (Wed.), 4 PM  #1322 (E6-2. 1st fl.)  Prof. Noejung Park (UNIST)  Phonon-driven spin-Floquet valleytro-magnetism file
69 October 15 (Tue.), 16:00 PM  #1323, E6-2  Prof. Pilkyung Moon  Moiré superlattices and graphene quasicrystal file
68 4월 18일(월), 15:30~  KI빌딩(E4), 강의실 B501 (5F)  Prof. Robert A. DiStasio Jr. (Cornell University)  First Principles Approaches for Intermolecular Interactions: From Gas-Phase Dimers to Liquid Water and Molecular Crystal Polymorphism file
67 2018. 6. 22 10:00am ~ 11:50am  E6-6, Lecture Room 119 (1F)  Prof. Sang Bok Lee, Dept. of Chemistry and Biochemistry, Univ. of Maryland  Success in Research Career file
66 NOV. 23 (Fri), 03:00 PM  E6-2. 2st fl. #2501  Prof. Sang-Jin Sin  Entanglement string and Spin Liquid with Holographic duality file
65 October 29 (Tue.), 10:00am  #1323 (E6-2, 1st fl.)  Prof. Se Kwon Kim  Unconventional Spin Transport in Quantum Materials file