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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.

 

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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
174 July 10 (Wed.), 04:00 PM-  Academic Cltural Complex (E9) 5층 스카이라운지  Prof. Sidney Nagel/Young-Kee Kim  Public Lectures file
173 2015/08/04, 11PM  B501, Room Red, KI bldg. 5nd fl.  Dr. Eric Jin Ser Lee(Univ. of Manitoba, Canada)  Propagation of ultrasound through two- and three-dimensional strongly scattering media
172 Jun. 1(Wed) 10:30 AM  BK21 Conference Room (#1318, E6-2)  Dr. Noriaki Horiuchi, Editor, Nature Photonics  Welcome to Nature Photonics
171 2015/03/13, 2PM  Connect Room, KI Bldg.    The 15th Innovative Workshop on Soft/Bio Materials file
170 2015/12/09, 11AM  E4(KI Building), Connect room (2nd fl.)  Arjun G. Yodh (University of Pennsylvania)  Functional Imaging & Monitoring of Brain & Breast with Diffuse Light
169 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
168 2015/07/23,1:30PM  E4, B401  Prof. Gilles Lérondel (Univ. of Technology of Troyes)  Enhanced ZnO based UV photonics and related applications file
167 Nov. 22th (Thur), 15:00  E6 Room(#1323)  Prof. Suprijadi Haryono  Experimental and Computational Study on Physical Properties based on Granular System file
166 May. 8th (Wed), 16:00  E6 Room(#1323)  Jieun Lee  Imaging valley dependent electron transport in 2D semiconductors file
165 August. 16th (Fri), 14:00  E6 Room(#1323)  Jinxing Zhang  Multiferroic and Magnetoelectric Effects by Tailoring Interfacial Chemistry and Physics in Correlated Oxides file
164 August. 1st (Thu), 14:00  E6 Room(#1323)  Hyeok Yoon  Low-density Superconductivity in SrTiO3 Probed by Planar Tunneling Spectroscopy file
163 August. 6th (TUE), 14:00  E6 Room(#1323)  Kanghyun Chu  Visualization of in-plane piezoresponse vector fields file
162 July 8(Mon), 14:00  E6, #1322  T. L. M. Guedes (Univ. of Konstanz)  Ultrabroadband squeezed pulses and their relation to relativity file
161 2015/10/23-12/4 10:30 AM  E6, #1501  Prof. YongKeun Park & Prof. Tae-Young Yoon  How to write a good scientific paper[Open lecture series]
160 2009/02/23-05/04  E6, 1501  안종현교수(성균관대) 외  Physics Colloquium : 2009 Spring file
159 2009/09/07-11/30  E6, 1501  이주영박사(KIAS) 외  Physics Colloquium : 2009 Fall file
158 2009/10/21, 4PM  E6, 1501  최석봉교수(서울대)  Interdimensional Universality of Dynamic Interfaces
157 2010/02/08-05/03  E6, 1501  최인수교수(서울대) 외  Physics Ciolloquium : 2010 Spring file
156 2010/09/06-12/06  E6, 1501  조호진기자(조선일보) 외  Physics Colloquium : 2010 Fall file
155 2010/02/14-05/09  E6, 1501  황철주(주성엔지니어링 사장) 외  Physics Colloquium - 2011 Spring file