Underwater Electrical Wire Explosion Experiment

The goal of the Underwater Electrical Wire Explosion (UEWE) project is to generate and study warm dense matter (WDM). WDM describes an extreme state of matter that lies in the transition region between condensed matter and plasma. It is often described as a strongly coupled dense plasma and thus not as an ideal plasma.

An effective method for generating WDM is underwater electrical wire explosion. For this method a pulsed-power setup can be utilized. In this particular setup two parallel-connected capacitors serve as the primary energy source. These can be charged to voltages of up to 40 kV and energies of up to 8 kJ.

To quickly discharge the capacitors, a cold cathode thyratron, or pseudo-spark switch, is used.  So current rise times of 10¹⁰ A/s and peak currents of over 100 kA can be reached. The current flows through a coaxial transmission line into the target, a thin tantalum wire. Therefore, the wire is heated rapidly and due to the surrounding water simultaneously compressed, generating a dense plasma.

In addition to current and voltage measurements, the wire explosion is also examined optically. snapshots with a CCD camera and time-resolved images with a streak camera are taken to measure the wire expansion, shock- and sound waves. Additionally, the wire explosion is investigated radiographically using proton microscopy to gain insights into the density distribution.