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
279 2017-05-12 13:30  E6-2. 1st fl. #1323  Topological Dirac insulator
278 2017-04-28 14:30  E6-2. 1st fl. #1323  Hot electron generation at surfaces and its impact to catalysis and renewable energy conversion
277 2016-10-18 15:00  E6-2. 1st fl. #1323  “Hybrid quantum systems with mechanical oscillators”
276 2016-04-12 16:00  E6-2. 1st fl. #1323  Confinement of Superconducting Vortices in Magnetic Force Microscopy
275 2016-04-05 16:00  E6-2. 1st fl. #1322  A new impurity solver for multi-orbital systems: adaptive truncation of the Hilbert space
274 2015-09-07 15:00  E6-2. 1st fl. #1318  Advanced Optical Materials and Devices at NRL
273 2016-09-21 16:00  E6-2. #2502(2nd fl.)  Entanglement probe of two-impurity Kondo physics
272 2016-09-29 16:00  E6-2. #2501(2nd fl.)  Exploring the phase diagram of BaBiO3: epic voyage of just another bad trip?
271 2016-11-10 16:00  E6-2. #1323(1st fl.)  Low Dimensional Active Plasmonics and Electron Optics in Graphene
270 2016-11-04 15:00  E6-2. #1323(1st fl.)  Quantum information experiments using few electron spins in semiconductors
269 2016-11-04 13:30  E6-2. #1323(1st fl.)  Exotic phenomena at oxide LaAlO3/SrTiO3 hetero-interface and their applications
268 2016-10-07 16:00  E6-2. #1323(1st fl.)  “Tilt engineering of 4d and 5d transition metal oxides?”
267 2016-10-07 13:30  E6-2. #1323(1st fl.)  “Symmetry and topology in transition metal dichalcogenide?”
266 2016-05-24 16:00  E6-2. #1323(1st fl.)  Electronic and magnetic properties of 2D transition-metal thiophosphates and tunability of magnetic order with carrier density
265 2016-05-11 16:00  E6-2. #1323(1st fl.)  The quest for novel high-temperature superconductors---Prospects and progress in iridates
264 2022-05-19 16:00  E6-2. #1323 & Zoom  Chasing Long Standing Neutrino Anomalies with MicroBooNE
263 2022-05-18 16:00  E6-2. #1323 & Zoom  Geometry, Algebra, and Quantum Field Theory
262 2022-05-12 16:00  E6-2. #1323 & Zoom  New frontiers of electroweak physics at the LHC
261 2022-05-11 16:00  E6-2. #1323 & Zoom  Gravity as a phenomenon in quantum dynamics
260 2015-07-15 14:00  E6-2,1323  Electronic and optical properties of titanate-based oxide superlattices