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
213 2016-11-18 10:30  #5318(5th fl.)  Non-equilibrium many-body spin dynamics in diamond
212 2016-10-27 16:00  #1323(E6-2)  Terahertz Metal Optics
211 2019-06-28 13:30  #1323, E6-2  Magnetic domains and domain wall conduction in pyrochlore iridate thin films and heterostructures file
210 2016-04-08 13:30  E6-2. 1st fl. #1501  Theoretical Overview of Iron-based superconductors and its future
209 2017-09-26 11:00  #1323 (E6-2. 1st fl.)  Time-resolved ARPES study of Dirac and topological materials
208 2019-11-01 14:30  E6-2. 1st fl. #1323  Squeezing the best out of 2D materials file
207 2019-04-19 14:30  E6-2. 1st fl. #1323  A family of finite-temperature electronic phase transitions in graphene multilayers file
206 2015-11-06 16:30  E6-2, #5318  Topological Dirac line nodes in centrosymmetric semimetals
205 2018-03-16 16:00  E6-2. 1st fl. #1323  Van der Waals Heterostructures from Quantum Transport to Ultrafast Optoelectronics file
204 2018-03-16 16:00  E6-2. 1st fl. #1323  Van der Waals Heterostructures from Quantum Transport to Ultrafast Optoelectronics file
203 2022-08-09 14:00  KI building (E4), Lecture Room Red (B501)  Quantum biology in fluorescent protein: a new model system to study quantum effects in biology file
202 2016-05-13 13:30  E6. #1501(1st fl.)  Aperiodic crystals in low dimensions
201 2018-04-11 16:00  #1323 (E6-2, 1st fl.)  Non-Gaussian states of multimode light generated via hybrid quantum information processing file
200 2017-05-12 13:30  E6-2. 1st fl. #1323  Topological Dirac insulator
199 2022-05-13 16:00  자연과학동(E6-2) 1st fl. #1323  High-fidelity iToffoli gate for fixed-frequency superconducting qubits file
198 2022-06-10 11:00  Online seminar  Record-quality two-dimensional electron systems file
197 2018-04-11 13:30  #1323 (E6-2, 1st fl.)  Probing 3D Structure and Physical Properties of Materials at the Single-Atom Level file
196 2018-10-15 16:00  #1323, E6-2  Universal properties of macroscopic current-carrying systems file
195 2016-09-02 16:00  E6-2(1st fl) #1323  Quantum Electrical Transport in Topological Insulator Nanowires
194 2016-09-02 14:30  E6-2(1st fl.), #1323  Nanoscale Thermal Physics: Seebeck Effect and Nanoscale Friction