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epr2014_chai.pdf2014-08-13 11:43:17Kil-Byoung Chai

Space- and time-resolved EUV images associated with magnetic reconnection in MHD-driven jets

Author: Kil-Byoung Chai
Requested Type: Poster Only
Submitted: 2014-05-28 12:44:12

Co-authors: P. M. Bellan

Contact Info:
Caltech
1200 E. California Blvd
Pasadena, CA   91125
USA

Abstract Text:
A high-speed extreme-ultra-violet (EUV) movie camera has been developed for imaging magnetic reconnection in the Caltech MHD-driven jet experiment [1]. A temporal resolution up to 10^7 fps can be achieved and the spatial resolution is about 5 mm. In order to achieve high speed, a fast, visible-light movie camera (up to 2*10^8 fps) is utilized with a fast-decaying YAG:Ce scintillator crystal that converts EUV radiation into visible light. A custom-designed Si/Mo multilayer mirror having central wavelength at 36 nm (equivalent to 34 eV photon energy) and 10 nm FWHM is used to focus EUV photons and form an image on the scintillator crystal. We found that the EUV images, obtained at the early phase when the initial plasma loops are merging into a single jet, are similar to what we have seen in visible light images: only a small, central part of jet becomes extremely bright where the magnetic reconnection takes place. On the other hand, the EUV images differ from visible light images when a kink instability occurs followed by a Rayleigh-Taylor instability: a small jet segment near the apex of the kinked jet becomes extremely bright in EUV whereas the visible light image dims somewhat at this location. We think this is associated with fast magnetic reconnection and so is a key toward understanding fast magnetic reconnection. Future plans include further investigation of fast magnetic reconnection and upgrade of optical sensitivity by better optical coupling to the scintillator crystal.

[1] K.-B. Chai and P. M. Bellan, Rev. Sci. Instrum. 84, 123504 (2013).

Characterization: 4.0

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Workshop on Exploratory Topics in Plasma and Fusion Research (EPR) and US-Japan Compact Torus (CT) Workshop
August 5-8, 2014
Madison, Wisconsin

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