Proposed MHD Research Subjects to SFG 1 Study

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Proposed MHD Research Subjects to SFG 1. Study of 3 -D characteristics of magnetic

Proposed MHD Research Subjects to SFG 1. Study of 3 -D characteristics of magnetic reconnection. 2. How can reconnection be controlled in tokamaks & ST’s? M. Yamada H. Ji et al

Current main issues for magnetic reconnection • Reconnection in terms of global flux and

Current main issues for magnetic reconnection • Reconnection in terms of global flux and energy inventory – Global field line evolution : 3 D aspects – Magnetic self-organization-specifically compare reconnection dynamics in RFP, tokamak, solar flares – Multiple reconnection layers in a large system – Impulsive reconnection • Identify main mechanisms for energy dissipation Particle acceleration and heating -Runaway electrons Effects of guide field (2 D &3 D) Effects of boundary conditions Ps&T PAC: More crosscutting research with main line research at PPPL

Study of Physics of Tearing Modes in MRX • • Tearing modes are important,

Study of Physics of Tearing Modes in MRX • • Tearing modes are important, but difficult to measure directly in fusion plasmas MRX offers unique opportunities to directly measure their growth as a function of key parameters Two operations possible: cohelicity merging where Bt is generated by plasma current, or guide-field operation where Bt is externally imposed Non-MHD physics should be important due to large ion gyroradius Yamada et al. PRL (1997) Key questions: 1. How is an island generated? 2. How dose it develop to a nonlinear (kink) state? 3. How does non-MHD physics affect such process?

Solar Flare Experiment on MRX Main Objectives (1) To determine stability or loss-of-equilibrium conditions

Solar Flare Experiment on MRX Main Objectives (1) To determine stability or loss-of-equilibrium conditions for a single flux rope, (2) To evaluate the effects of line tying of magnetic flux rope plasma => No disruption found (3) To investigate nonlinear state of the of kink modes during eruptive phenomena

Experimental Setup MRX vacuum vessel flare Equ ili briu m. F ield electrodes D

Experimental Setup MRX vacuum vessel flare Equ ili briu m. F ield electrodes D ` Guide Field ` a Magnetic probes Guide Field Equilibrium Field Coils D: 2 R FLARE Diameter a: Flare radius Coils

Electrodes inside the MRX vacuum vessel Flare photos taken with a commercial Canon Powershot

Electrodes inside the MRX vacuum vessel Flare photos taken with a commercial Canon Powershot 100 µs exposure

Safety factor q determines the stability of simulated flux loop in MRX Rp qa

Safety factor q determines the stability of simulated flux loop in MRX Rp qa value Arc center position Plasma position Btoroidal = 360 G STABLE UNSTABLE Bpvectors & j counters (color): Framing camera photos Btoroidal = 1055 G t( s)