Linear Pinch

Author: Jay & Tim

This was the first linear pinch experiment we have setup. It uses RF pre-ionization to make the plasma conductive. Then, via an externally triggered spark gap, a 30kV, 3.5uF cap bank is placed across the two hefty axial copper leads.

The initial linear pinch chamber is a glass break with 6-inch conflat flanges on each end. The left side is held at ground potential and the right side is pulsed HV.

The coil surrounding the glass tube and the vacuum variable capacitor in the background form a high-Q tank circuit to pre-ionize the plasma. The leads coming in from the top of the image connect the RF generator to the 50-ohm points of the tank circuit.

Using my old Jenning’s vacuum tube RF voltmeter I was able to find resonance and measure the peak voltage.

RF pre-ionization of air.

RF pre-ionization of Krypton.

Dumping 30kV, 3.5uF across tube (via a triggered spark gap), the pinch is formed!

Shortly thereafter there is the onset of instability.