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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
54 November 29 (Thu.), 16:00 PM  #1323, E6-2  Dr. Kee suk Hong  양자 칸델라 실현을 위한 단일 광자 발생장치 개발 file
53 November 5 (Tue.), 4:00 PM  #1323, E6-2  Dr. Shik Shin  Study on nanomaterials by the development of ultrahigh resolution laser-photoelectron microscopy (PEEM) file
52 November 7 (Thu.), 16:00 PM  #1323, E6-2  Prof. Je-Hyung Kim  Integrated quantum photonics with solid-state quantum emitters file
51 November 8 (Thu.), 16:00 PM  #1323, E6-2  이종완 박사  Conformality lost file
50 Oct. 07 (Fri), 1:30 PM  E6-2. #1323(1st fl.)  Dr. Suk Bum Chung, IBS-CCES , Seoul National University  “Symmetry and topology in transition metal dichalcogenide?”
49 Oct. 07 (Fri), 4:00 PM  E6-2. #1323(1st fl.)  Dr. Choong Hyun Kim,IBS-CCES, Seoul National University  “Tilt engineering of 4d and 5d transition metal oxides?”
48 Oct. 10(Tue) 4PM  E6-2 #1323  김성웅 교수 (성균관대학교 에너지과학과)  Discovery of New 2D Materials with Diverse Physical Properties
47 Oct. 12 (Fri.), 02:30 PM  E6-2. 1st fl. #1323  Dr. Daniel Kyungdeock Park  Quantum Advantage in Learning Parity with Noise file
46 Oct. 12 (Fri.), 04:00 PM  E6-2. 1st fl. #1323  Dr. HyungWoo Lee  Direct observation of a two-dimensional hole gas at oxide interfaces file
45 Oct. 17th (Mon) 11:00 AM  #1323,(E6-2, 1st fl.)  Nguyen Quang Liem, Institute of Materials Science, VAST, Viettnam  IMS and examples of the studies on optoelectronic materials
44 Oct. 18 (Tue.), 1:30 PM  1st fl. #1323(E6-2)  Dr. Chan-Ho Yang, Department of Physics, KAIST  "Visualization of oxygen vacancy in motion and the interplay with electronic conduction"
43 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”
42 Oct. 25 (Fri), 15:00 ~  #1323, E6-2  Daesu Lee,Junwoo Son,MyungJoon Han ,Siheon Ryee,Eun-Gook Moon  Physics Seminar file
41 Oct. 27th(Thu) 4PM  #1323(E6-2)  Dr. 이 강 희, KAIST, Mechnical Engineering  Terahertz Metal Optics
40 October 11 (Thu.), 16:00 PM  #1323, E6-2  Prof. Joung-Real Ahn  Dirac electrons in a graphene quasicrystal file
39 October 15 (Mon.), 16:00 PM  #1323, E6-2  Dr. Yongjoo Baek  Universal properties of macroscopic current-carrying systems file
38 October 15 (Tue.), 16:00 PM  #1323, E6-2  Prof. Pilkyung Moon  Moiré superlattices and graphene quasicrystal file
37 October 16 (Tue.), 10:00 AM  #1323, E6-2  Dr. Won-Ki Cho  Capturing protein cluster dynamics and gene expression output in live cells file
36 October 16 (Wed), 4:00pm  #1323 (E6-2, 1st fl.)  Dr. Jaewon Song  Emergent black holes and monopoles from quantum fields file
35 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