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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
65 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
64 November 7 (Thu.), 16:00 PM  #1323, E6-2  Prof. Je-Hyung Kim  Integrated quantum photonics with solid-state quantum emitters file
63 November 8 (Thu.), 16:00 PM  #1323, E6-2  이종완 박사  Conformality lost file
62 Oct 23 (Fri.), 14:00 PM  E6-2 #1323  Prof. Ivan Savenko (University of Science and Technology & IBS PCS)  Plasmon spectroscopy of low-dimensional superconductors in fluctuating regime file
61 Oct 9 (Fri), 09:00 AM  https://kaist.zoom.us/j/85161896513?pwd=U3pwWFFZaWVRamxDZUR5REhNeVk0UT09  Prof. Tim Hsieh (Perimeter Institute)  Quantum Many-Body Simulation file
60 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?”
59 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?”
58 Oct. 10(Tue) 4PM  E6-2 #1323  김성웅 교수 (성균관대학교 에너지과학과)  Discovery of New 2D Materials with Diverse Physical Properties
57 Oct. 12 (Fri.), 02:30 PM  E6-2. 1st fl. #1323  Dr. Daniel Kyungdeock Park  Quantum Advantage in Learning Parity with Noise file
56 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
55 Oct. 15, 4pm  (https://kaist.zoom.us/j/93997220310)  정현석 교수님 (SNU)  Towards resource-efficient and fault-tolerant quantum computation with nonclassical light
54 Oct. 16 (Fri.), 02:30 PM  https://kaist.zoom.us/j/89198078609  Dr. Chulki Kim  Nanoscale magnetic resonance detection towards nano MRI file
53 Oct. 16 (Fri.), 04:00 PM  https://kaist.zoom.us/j/89198078609  Dr. Daesu Lee  Hidden room-temperature ferroelectricity in CaTiO3 revealed by a metastable octahedral rotation pattern file
52 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
51 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"
50 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”
49 Oct. 25 (Fri), 15:00 ~  #1323, E6-2  Daesu Lee,Junwoo Son,MyungJoon Han ,Siheon Ryee,Eun-Gook Moon  Physics Seminar file
48 Oct. 27th(Thu) 4PM  #1323(E6-2)  Dr. 이 강 희, KAIST, Mechnical Engineering  Terahertz Metal Optics
47 October 11 (Thu.), 16:00 PM  #1323, E6-2  Prof. Joung-Real Ahn  Dirac electrons in a graphene quasicrystal file
46 October 15 (Mon.), 16:00 PM  #1323, E6-2  Dr. Yongjoo Baek  Universal properties of macroscopic current-carrying systems file