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
502 2023-10-11 16:00  E6-2, Rm2502  [High Energy Theory Seminar] Axion Magnetic Resonance
501 2023-10-04 16:00  E6-2, #2502  [High-Energy Theory Seminar] Moving towards quantum technologies: the case of quantum batteries
500 2023-09-27 16:00  E6, Rm#2501  Chiral Magnets: Domain-Wall Skyrmions and String Theory Realization
499 2023-09-26 16:00  E6-2, #2502  [High Energy Theory Seminar]A new step in interacting dark sector cosmologies
498 2023-09-21 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  [CAPP seminar] Axion Magnetic Resonance file
497 2023-09-18 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  [CAPP Seminar] Searching for axions in quantum vacuum birefringence file
496 2023-09-18 11:00  E6-2, #1322  Magic polarisation trapping of polar molecules for tunable dipolar interactions file
495 2023-09-14 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  [CAPP seminar] Dark matter searches in Water Cherenkov Detectors file
494 2023-09-13 16:00  E6-2, #2502  [High Energy Theory Seminar] Cosmic Birefringence from Dark Photon
493 2023-09-07 12:00  E6-2 #1323  2023 가을학기 광학분야 및 응집물리 특별세미나 전체 일정 file
492 2023-08-29 16:00  E6-2, #2502  [High Energy Theory Seminar] Towards string loop corrections in Calabi-Yau orientifold compactifications.
491 2023-08-24 12:00  E6-1 #1501  2023 가을학기 콜로키움 전체 일정 file
490 2023-08-24 11:00  E6, Rm#1323  Advancing magnonic metamaterials: spin waves in nanomagnetic arrays
489 2023-08-23 16:00  E6-2, #1322  [High Energy Theory Seminar] A spacetime tensor network for AdS3/CFT2
488 2023-07-26 10:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  [CAPP Seminar] Am Expansive Search for Dark Matter with ADMX and DM Radio
487 2023-07-20 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  [CAPP Seminar] Cosmoparticle Physics of Dark Universe file
486 2023-07-19 16:00  E6-2, #1323  [High-Energy Theory Seminar]Deriving the Simplest Gauge-String Duality
485 2023-07-18 11:00  E6-2, #1323  Non-Hermitian Casimir Effect of Magnons
484 2023-07-14 11:00  E6-2 #1501  Interfaces engineering of thin film oxides
483 2023-07-12 11:00  E6-2, #1323  Study of spin-1/2 antiferromagnetic kagome Heisenberg model by symmetric projected entangled simplex states