A "pinch" is the compression of an electrically conducting filament by magnetic forces. The conductor is usually a plasma, but could also be a solid or liquid metal.
Pinches were the first device used by mankind for controlled nuclear fusion.
The phenomenon may also be referred to as a "
Bennett pinch" , "electromagnetic pinch", "magnetic pinch", "pinch effect" or "plasma pinch".
Pinches occur naturally in electrical discharges such as lightning bolts, the aurora, current sheets, and solar flares.
Pinches exist in laboratories and in nature. Pinches differ in their geometry and operating forces. These include:
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Uncontrolled: any time an electric current moves in large amounts a magnetic force can pull together plasma. This can be insufficient for fusion.
# Sheet pinch: an astrophysical effect, this arises from vast sheets of charge particles.
# Z-pinch: the current runs down the axis of the cylinder while the magnetic field is azimuthal
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Theta pinch: the magnetic field runs down the axis of the cylinder, while the electric field is in the azimuthal direction
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Screw pinch: a combination of a Z pinch and theta pinch
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Reversed field pinch: This is an attempt to do a Z-pinch inside an endless loop. The plasma has an internal magnetic field. As you move out from the center of this ring, the magnetic field reverses direction. Also called a toroidal pinch.
#
Inverse pinch: An early fusion concept, this device consisted of a rod surrounded by plasma.
Current traveled through the plasma and returned along the center rod. This geometry was slightly different than a z-pinch in that the conductor was in the center, not the sides.
# Cylindrical pinch
# Orthogonal pinch effect
#
Ware pinch: an pinch that happens inside Tokamaks. This is when particles inside the
Banana orbit condense together.
#MAGLIF. This is a combination of a Z-pinch and a laser beam to stop loss of material at the end.
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- published: 08 Sep 2015
- views: 226