The Dense Plasma Focus: A Versatile Dense Pinch for Diverse Applications

The dense plasma focus (DPF) is a Z-pinch that has been studied for 50 years. Within ten years of its discovery by Fillipov and Fillipova in Russia and Mather in the USA, this dense pinch was scaled up to 2-MA currents and neutron outputs of ~ 10¹²/pulse. More remarkable is the fact that most of the relevant physics and scaling laws were elucidated within this first decade. The subsequent period has seen this type of pinch used as a teaching tool, developed as a portable neutron source for security applications, as a soft X-ray source for lithography, and as an energetic ion source for nanofabrication applications. This review builds upon several prior reviews. From the plasma physics standpoint, DPF physics is examined in light of fast Z-pinches to examine the similarities. More cross-fertilization between the two communities is suggested as a means to improve both types of pinches. From the applications standpoint, the many uses of DPFs are summarized to demonstrate the versatility of these pinches. Their ease of assembly and relatively low voltage operation have allowed DPFs to be disseminated worldwide as fusion testbeds (unlike their fast Z-pinch counterparts). Smaller or less economically developed nations have made valuable contributions to our understanding of the physics, as evidenced by the rich lode of publications that have advanced the field.