In order to understand the behaviour of "solar flares", an experiment was constructed to simulate this kind of
plasmas in our laboratory. Above two electrodes an arc-shaped magnetic field is located. One of these electrodes
can be charged up to +3kV, the other one symmetrically down to -3kV. Hydrogen gas is injected in front of these
electrodes and an electrical discharge is initiated.
This discharge only lasts for some microseconds, so a fast framing camera is necessary to follow the evolution
of the plasma flare. Also other detecting methods (triple probe, pick up coils) are in development.
Progress of the experiment
The first image (on the left hand side) shows us the ground state of the experiment. The green streamlines of the
magnetic field are created by permanent magnets. In the first step of the experiment hydrogen gas is injected
into the chamber (image in the middle). When the hydrogen gas has spread out in front of the electrodes, the voltage
between both of the electrodes is switched on and the plasma is ignited (on the right hand side). In some circumstances the
plasma arc is drawn together. This effect is called self-pinching.
Modification of the plasma source
In order to build a plasma source which fulfils the model for solar flares from Titov und Demoulin (left picture, 1999),
a new one was constructed (right picture). The electrodes can be charged up, like the former electrodes, to +3 kV
one the one side and to -3 kV on the other side.
The current setup is not longer been driven by a permanent magnet but a line current.
The permanent magnets were replaced by a line current between the
both electrodes which can create a magnetic field strength of about 0.4 T in a distance of 4 cm around the line
current. Therefor a current of about 25 kA is needed which will be provided by a pulse forming network.