Laboratory simulation of solar prominences

Solar prominences are large arch-shaped structures observable in the solar corona. These often have a twist and occasionally become unstable, ejecting plasma and magnetic flux out from the sun. A famous example of an exploding prominence is the 1973 Skylab photo shown to the right.

The physics of solar prominence instability is believed to be governed by magnetic forces and magnetic helicity issues. It is thought that instability occurs when a magnetic flux tube becomes excessively twisted.

 
We have constructed a specially designed magnetized plasma gun which produces arched, erupting, twisted flux tubes (see photo on right) similar to erupting prominences. The plasma gun is based on spheromak technology but, unlike spheromaks, has a non-coaxial geometry so as to produce arch shaped flux tubes. Also, the vacuum chamber wall is located far away so that the erupting flux tube is unaffected by wall image currents. This laboratory simulation of solar prominences is based on the premise that the physics of erupting solar prominences is analogous to the physics of the formation of laboratory spheromaks. The image to the left shows a photo of a simulation of a prominence obtained in our lab. Distance between footpoints is approximately 10 cm. Diagnostics include a high speed camera and measurements of magnetic flux, current , and voltage.  
New Animated solar gun images Vacuum chamber, plasma gun 3D photos

 Solar gun images: twisting, erupting lab plasma

Images from numerical model (original gun) Original solar gun images: complex structure
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