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Experimental Studies of the Hall Effect in MRX. Y. Ren, S. Gerhardt , A. Kuritsyn, H. Ji, R. Kulsrud, M. Yamada Princeton Plasma Physics Laboratory. Outline. The Hall effect in numerical simulation and space observations. - PowerPoint PPT Presentation
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Experimental Studies of the Hall Effect in MRX
Y. Ren, S. Gerhardt , A. Kuritsyn, H. Ji, R. Kulsrud, M. Yamada
Princeton Plasma Physics Laboratory
Outline
• The Hall effect in numerical simulation and space observations.
• Experimental study of the Hall effects during magnetic reconnection in the MRX.
• Summary
Two Models to Fast Magnetic Reconnection
Generalized Sweet-Parker model with anomalous resistivity.
Two-fluid MHD model in which electrons and ions decouple within the scale of order c/pi
and the reconnection rate is enhanced by the dispersive nature of the whistler wave.
The Hall Effects During Reconnection Shown in 2D Simulations
The out-of-plane magnetic field is generated during reconnection.
P. L. Pritchett, JGR 2001
Different motions of ions and electrons show the decoupling of them, thus generating the in-plane Hall current and the out-of-plane magnetic field.
Space observation showing signs of the Hall effects
The out-of-plane magnetic field.
F.S. Mozer et al., P.R.L. 2002
Fine structure probe array
• A magnetic probe array with spatial resolution up to 1.25 mm and 71 channels is used to search for the signs of the Hall effects.
Fine structure probe
The Construction of the Fine Structure Probe (I)
The coils are hand-winded with 48 AWG magnet wire to 160 turns and approximately 1mm in diameter and 2 mm in length.
D. Cylinder
The small coils are glued to an alumina rod.
The Construction of the Fine Structure Probe (II)
Aluminized mylar is used to provide electrostatic shielding. The 3dB point of the frequency response is about 1MHz.
Fine structure probe
The probe location• The fine structure probe is inserted in the radial direction in the MRX
at two locations, Z=7cm and Z=-7cm, are extensively studied.71-channel magnetic probe array
Comparison with numerical simulation (II)
71-channel probe location Pritchett, JGR , 2001
1.8 c/pi
(1)
VZe/VA» 0.7
(underestimate VZe)
(2) Ve/VA» 1.2 in numerical simulation
Electron
Ion
Quadrupole field in Argon Plasma
pic ~14 cm, assuming Z=1Fill pressure 2.1 mTor.
~0.3, ~90ZHall BB mfp