Transmission Line Code Modeling of the Plasma Flow Switch

The plasma flow switch (PFS) utilizes the motion of a high density plasma discharge to accumulate and then release magnetic energy at multimegampere, rrul t imegajoul e 1 eve 1 s •1 Energy input to a coaxial plasma gun occurs in severa l microseconds as t he annular plasma discharge is accelerated axially along the center conductor . Energy is released to a load in a few hundred nanoseconds as this plasma is expelled off the end of the center conductor. Low density plasma upstream of the axially-moving discharge can limft the flow of electromagnet i c power to speeds related to the local Alfven speed . The wave transit time between the 1 oad and the magnetic energy store can compare with the desired energy extract i on time. The effects of finite wave speed have bee2 investigated using approximate acoustic ana lyses. The present paper utilizes a transmission li ne code with varying time and i IT'(Jedance e 1 ements to model wave transit effects during PFS operation including commutation and load dynamics .