Historical research guide · 0588 · 2015

Physical processes taking place in dense plasma focus devices at the interaction of hot plasma and fast ion streams with materials under test

V A Gribkov

In one minute

A dense plasma focus converts electrical energy into a brief plasma pinch. A capacitor bank discharges between coaxial electrodes; a current sheet collapses onto the axis, creating hot plasma, fast electron and ion beams, X-rays and neutrons over nanoseconds. Gribkov surveys material-testing experiments using devices from 1 kilojoule to 1 megajoule. The reported peak radiation power flux can reach 10¹³ watts per square centimetre in some cases. The paper focuses on what must be understood to use the pulse: jet formation, sudden current interruption, super-Alfvén ion-beam motion, secondary plasma and shock waves in both plasma and solid targets. It reports more than thirty laboratories using DPF systems to test candidate fusion-reactor materials, modify surfaces and form nanostructures. This is an abstract-only source, so the guide confines its claims to the publisher’s abstract.

Connection

Chapter 9 is about self-organised plasma structures that hold together and carry energy, and the dense plasma focus is the one such structure that hundreds of people have built on a laboratory bench and instrumented at nanosecond resolution, so it is where the vocabulary for the rest of the chapter comes from. Chapter 12 gets the practical end: the reason more than thirty laboratories run these devices is that the pulse they deliver to a target is the closest available stand-in for what a fusion reactor wall will have to survive. Read it beside the aneutronic programme at /library/stm-05100e66da, the numerical model of the same machine at /library/stm-fbd01b5713, and the tens-of-joules pinch at /library/stm-12f5d53acb.

From the source

A dense plasma focus device is a source of powerful streams of penetrating radiations — hot plasma, fast electron and ion beams, x-rays and neutrons — with pulse durations on the nanosecond scale, and the power flux densities of those radiation types may in certain cases reach values up to ten to the thirteenth watts per square centimetre.Abstract, opening two sentences
More than thirty laboratories worldwide currently use these devices in radiation material science. The named areas of implementation are testing materials that are candidates for use in modern fusion reactors of both types, modification of surface layers to improve their properties, and production of nanostructures on those surfaces.Abstract, third and fourth sentences
The physical mechanisms the paper treats are named explicitly: jet formation, the current abruption phenomenon, super-Alfvén ion beam propagation both inside and outside the dense plasma focus plasma, generation of secondary plasma, and the formation of shock waves both in the plasma and inside a solid-state target.Abstract, the sentence beginning ‘Among them mechanisms of a jet formation’
The experimental results illustrating those mechanisms come from four dense plasma focus devices whose bank energies span the range from one kilojoule to one megajoule — the same class of physics examined across three orders of magnitude in stored energy.Abstract, the sentence beginning ‘In this paper, the most important issues’
The events are resolved with nanosecond time-resolved techniques — electric probes, laser interferometry, frame self-luminescent imaging, x-ray and neutron probes — and the irradiated specimens are then analysed with optical and scanning electron microscopy, local x-ray spectral and structure analysis, atomic force microscopy, a portable x-ray diffractometer combining single-photon detection with high spectroscopic and angular resolution, an x-ray microCT system, and microhardness measurements.Abstract, the two closing sentences on instrumentation
Gribkov frames the whole exercise as a prerequisite rather than a result: to use a dense plasma focus correctly in these applications it is necessary first to understand how the radiations are generated, how they move inside and outside the pinch, and how those streams interact with targets. That is the open work the paper sets out to advance.Abstract, the sentence beginning ‘To use a DPF correctly in these applications’

The way in

https://doi.org/10.1088/0741-3335/57/6/065010

Historical source-access record. This guide links to the original; it does not reproduce the paper text.

Published as Plasma Physics and Controlled Fusion 57, 065010 (2015); received 20 January 2015, accepted 25 March 2015, published 22 April 2015. Author affiliations as given on the article: the Institute of Plasma Physics and Laser Microfusion, Warsaw, and the A A Baikov Institute of Metallurgy and Material Science of the Russian Academy of Sciences, Moscow. LICENCE. No Creative Commons statement exists on either side: the Crossref record for this DOI carries only IOP’s copyright and text-and-data-mining pages, and the Unpaywall record returns oa_status bronze with a null licence, which means free to read at the publisher and nothing more. TEXT. The full text could not be reached. IOP’s server answers automated requests for both the article page and its PDF with a bot-manager challenge, the Semantic Scholar record has the abstract elided at the publisher’s request, no repository or preprint copy is recorded for this DOI, and the Internet Archive holds no snapshot of either URL. The abstract below was therefore taken word-for-word from the publisher’s own article page and is complete; superscripts lost in extraction are restored, so the power flux density reads ten to the thirteenth watts per square centimetre. The summary and the claims are drawn from that abstract and from the verified bibliographic record, and the locators point to it rather than to sections of the body.

How to cite it

V A Gribkov (2015) Physical processes taking place in dense plasma focus devices at the interaction of hot plasma and fast ion streams with materials under test doi:10.1088/0741-3335/57/6/065010

Where it sits in the curriculum

Fusion machines: pinches, focus devices and inertial drivers