Critical circuit parameters in producing a toroidal air plasma

A multi-millisecond duration, toroidal air plasma with electron density of 10¹⁴-10¹⁵ cm^-3 has been developed at the University of Missouri-Columbia. An exploding wire is used to first form the plasma and a secondary discharge region is used to further heat and impart momentum. Using this method of post discharge heating, we have been able to produce a self-confined, self-stabilized, toroidal air plasma, or TAP. A study of circuit parameters has been conducted to better understand the critical factors in the formation and evolution of the TAP. Circuit inductance and load resistance has been varied to determine the critical aspects of the formation of the TAP. A full diagnostic suite of pressure sensors, high speed photography, as well as current and voltage measurements, have been utilized to observe the TAP. Results from these experiments are presented as well as the experimental set up including the high voltage driving circuit.