Discharge plasma channels have been investigated in recent
years at Gesellschaft für Schwerionenforschung–Darmstadt
(GSI) and at the Lawrence Berkeley National Laboratory in Berkeley,
California, in a number of experiments. A short summary of the
experimental work at Berkeley and GSI is given. Different
initiation mechanisms for gas discharges of up to 60 kA were
studied and compared. In the Berkeley experiments, laser ionization
of organic vapors in a buffer gas was used to initiate and direct
the discharge while at GSI, laser gas heating and ion-beam-induced
gas ionization were tested as initiation mechanisms. These three
initiation techniques are compared and the stability of the
resulting discharge channels is discussed. A discharge current
of 50 kA, a channel diameter well below 1 cm, a pointing stability
better than 200 μm, and MHD stability of more than 10 μs
have been demonstrated simultaneously in the recent experiments.
These parameters are sufficient or close to the requirements
of a reactor application depending on the details of the target
design. The experimental results show that transport channels
work with sufficient stability, reproducibility, and ion optical
properties for a wide pressure range of discharge gases and
pressures.