Laboratory experiments relevant to mesospheric clouds, Saturn’s rings & astrophysical jets
2016.05.31 17:07
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.
댓글 0
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 |
95 | May 31 (Tue.) 4 PM | #1323(E6-2, 1st fl.) | Dr. Kimin Kim, KAIST | Understanding 3D tokamak physics towards advanced control of toroidal plasma |
94 | 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 |
93 | Nov. 11th(Fri), 1:30 p.m. | #1323(E6-2. 1st fl.) | Dr. Keun Su Kim, POSTECH | Bandgap Engineering of Black Phosphorus |
92 | November 29 (Thu.), 16:00 PM | #1323, E6-2 | Dr. Kee suk Hong |
양자 칸델라 실현을 위한 단일 광자 발생장치 개발
![]() |
91 | 2015/11/24, 4PM | E6-2, #1323 | Dr. Kab-Jin Kim (Institute for Chemical Research, Kyoto University, Japan) | Topology-based understanding of spin dynamics in inhomogeneously magnetized systems |
90 | Jul. 08 (Fri.) 2PM | #1323(E6-2. 1st fl.) | Dr. Junhyun Lee, Harvard University | Electronic quasiparticles in the quantum dimer model |
89 | Oct. 18 (Tue.), 3PM | E6-2. 1st fl. #1323 | Dr. JunHo Suh, Korea Research Institute of Standards and Science | “Hybrid quantum systems with mechanical oscillators” |
88 | 2015/12/17, 11:00AM | E4(KI Building), Matrix Hall (2nd fl.) | Dr. Jung-Hoon Park (Purdue University) | Wavefront engineering for in-vivo Deep brain imaging |
87 | June 27 (Wed.), 13:30 PM | #1323, E6-2 | Dr. Jung Sik Park |
Magnetic reversal of artificial spin ice
![]() |
86 | July. 14 (Fri.), 3:00 PM | #1323 (E6-2. 1st fl.) | Dr. Jun Hyun Lee / University of Maryland |
Chiral anomaly in disordered Weyl semimetals
![]() |
85 | Nov. 1 (Fri.), 04:00 PM | E6-2. 1st fl. #1323 | Dr. Ju-Jin Kim |
Electron transport through weak-bonded contact metal with low dimensional nano-material
![]() |
84 | Sep. 27 (Fri.), 02:30 PM | E6-2. 1st fl. #1323 | Dr. Joon Sue Lee |
Spin-charge conversion in topological insulators for spintronic applications
![]() |
83 | Dec. 7 (Fri.), 04:00 PM | E6-2. 1st fl. #1323 | Dr. Joon Ho Jang |
Novel probes of interacting electrons in 2D systems
![]() |
82 | October 19 (Fri.), 10:00 AM | #1323, E6-2 | Dr. Jongsoo Yoo |
Energy conversion processes during magnetic reconnection in a laboratory plasma
![]() |
81 | Nov. 04 (Fri), 1:30 PM | E6-2. #1323(1st fl.) | Dr. Jonghyun Song, Department of Physics, Chungnam National University | Exotic phenomena at oxide LaAlO3/SrTiO3 hetero-interface and their applications |
80 | 2015/08/03,10:30AM | E6-2, #1323 (Seminar Room) | Dr. Jonghee Yoo (Fermi National Accelerator Laboratory, USA ) | Axion Search |
79 | Apr. 01 (Fri.) 4:15 PM | E6-2. 1st fl. #1501 | Dr. JONG SOO LIM, KIAS | Cotunneling drag effect in Coulomb-coupled quantum dots |
78 | December 3 (Tue.), 4:00 PM | #1323, E6-2 | Dr. Jong Mok Ok |
Toward Quantum Materials with Correlated Oxides
![]() |
77 | Mar. 2nd (Thu), 4:00 p.m | #1323(E6-2. 1st fl.) | Dr. Jonathan Denlinger, Lawrence Berkeley National Lab | “Progress in the comparison of ARPES to DMFT for d and f strongly correlated electron systems” |
76 | Dec. 8(Thu) 4p.m. | #1323(E6-2. 1st fl.) | Dr. Jinhyoung Lee, Hanyang University | Dynamical Resonance between Two Optical Cavities via Optomechanical Oscillator |