visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
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
79 Apr. 12 (Tue.), 4 PM  E6-2. 1st fl. #1323  Dr. Jeehoon Kim, POSTECH  Confinement of Superconducting Vortices in Magnetic Force Microscopy
78 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
77 Apr. 08 (Fri.), 4:00 PM  E6-2. 5st fl. #1501  Dr. Changyoung Kim, SEOUL NATIONAL UNIV.  Spectroscopic studies of iron-based superconductors : what have we learned?
76 Apr. 08 (Fri.), 13:30 PM  E6-2. 1st fl. #1501  Dr. Yunkyu Bang, Chonnam National Univ.  Theoretical Overview of Iron-based superconductors and its future
75 Apr. 01 (Fri.) 4:15 PM  E6-2. 1st fl. #1501  Dr. JONG SOO LIM, KIAS  Cotunneling drag effect in Coulomb-coupled quantum dots
74 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
73 8/19 (Mon), 10:00~11:30, 8/22 (Thur), 10:00~11:30  Rm. 1322, E6-2  Nicolas Treps  Tutorials on Multimode Quantum Optics in the Continuous Variable Regime file
72 5월 17일(화), 11:00 ~ 12:00  창의학습관(E11), 406호  방준혁 박사(Korea Basic Science Institute, KBSI)  The CERN Resonant WISP Search: Development, Results and Lesson-Learned
71 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
70 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
69 3 PM, 12 Jun (Wed), 2019  Rm# 1323, E6-2  Dr. Minyoung You  The relation between free and interacting fermionic SPT phases file
68 2019. 8. 22 4PM & 8. 23 3PM  #1323, E6-2  Prof. Andrew N Cleland  Physics and Applications in Nanoelectronics and Nonomechanics file
67 2019. 7. 16(화)  Rm. 1323 (E6-2)  Prof. Sidney Nagel  2019 Physics Distinguished Lecture file
66 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
65 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
64 2017/03/21 - 06/08  Seminar Room 1323  조길영 박사(KAIST) 외  Spring 2017: Physics Seminar Serises file
63 2017/03/06 - 05/29  Seminar Room 1501  이종봉 박사 (POSTECH) 외  Spring 2017: Physics Colloquium file
62 2017.1.9(Mon), 4PM  Lecture Hall, College of Natural Sciences [#1501,E6-2]  Prof. John Michael Kosterlitz, Brown University  Topological Defects and Phase Transitions" file