visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
날짜 2016-06-01 16:00 
일시 Jun 1 (Wed) 4 PM 
장소 #1323(E6-2 1st fl.) 
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 날짜 장소 제목
공지 2022-10-24 16:00  E6 #1501(공동강의실)  Physics Colloquim(Fall 2022)
공지 2022-09-21 10:30  E6-1 #1501  [Update 세미나 영상] Distinguished Lecture 'The Magic of Moiré Quantum Matter' Prof. Pablo Jarillo-Herrero(Department of Physics, MIT)
공지 2022-11-11 11:00  E6-2 #1323  [Update 세미나영상] (응집물리 세미나) Honeycomb oxide heterostructures for quantum spin liquid
공지 2022-10-28 11:00  E6-2 #1323  [Update 세미나영상] (응집물리 세미나) Machine-Learning-Guided Prediction models and Materials discovery for high Tc cuprates
공지 2022-10-07 11:00  E6-2 #1323  [Update 세미나 영상] (응집물리 세미나) Competing orders in a vanadium-based kagome metal monolayer
공지 2022-09-23 11:00  E6-2 #1323  [Update 세미나 영상] (응집물리 세미나) Steady Floquet-Andreev states in graphene Josephson junctions
공지 2022-09-22 11:00  E6-1 #1323  2022 가을학기 응집물리 및 광학 세미나 전체 일정
60 2018-10-15 16:00  #1323, E6-2  Universal properties of macroscopic current-carrying systems file
59 2018-10-11 16:00  #1323, E6-2  Dirac electrons in a graphene quasicrystal file
58 2018-10-04 16:00  #1323, E6-2  Engineering light absorption in an ultrathin semiconductor metafilm file
57 2018-09-20 16:00  #1323, E6-2  Toward Cancer Treatment Using Terahertz Radiation: Demethylation of Cancer DNA file
56 2018-09-20 16:00  #1323, E6-2  Toward Cancer Treatment Using Terahertz Radiation: Demethylation of Cancer DNA file
55 2018-09-05 16:00  #1323, E6-2  Shining a light on fractional excitations file
54 2018-07-09 14:00  #1323, E6-2  The principles of collective learning file
53 2018-07-27 13:30  #1323, E6-2  Magnetic reversal of artificial spin ice file
52 2018-07-27 13:30  #1323, E6-2  Magnetic reversal of artificial spin ice file
51 2018-06-22 16:00  #1323, E6-2  Tuning functional properties of BiFeO3 films using strain and growth chemistry file
50 2018-06-22 16:00  #1323, E6-2  Tuning functional properties of BiFeO3 films using strain and growth chemistry file
49 2018-05-31 16:00  #1323, E6-2  Dynamic control of optical properties with gated-graphene metamaterials file
48 2018-05-29 16:00  #1323, E6-2  Investigation on metal nanostructure/semiconductor junction and its applications file
47 2018-05-09 16:00  #1323, E6-2  Recent advances in thermoelectric bulk composites file
46 2019-09-18 16:00  Seminar Room #1323  Fall 2019: Physics Seminar Serises file
45 2017-03-02 16:00  #1323(E6-2. 1st fl.)  “Progress in the comparison of ARPES to DMFT for d and f strongly correlated electron systems”
44 2017-02-01 14:00  #1323(E6-2. 1st fl.)  Quantum electron optics using flying electrons
43 2016-12-09 13:30  #1323(E6-2. 1st fl.)  Entanglement area law in strongly-correlated systems
42 2016-12-8 16:00  #1323(E6-2. 1st fl.)  Dynamical Resonance between Two Optical Cavities via Optomechanical Oscillator
41 2016-11-29 16:00  #1323(E6-2. 1st fl.)  Symmetry Protected Kondo Metals and Their Phase Transitions