Soft x-ray studies of plasma-focus pinch structures in PF-1000U experiments

Sadowski, M.; Paduch, M.; Składnik‐Sadowska, E.; Surala, W.; Zaloga, D.; Miklaszewski, R.; Zielinska, E.; Tomaszewski, K.

doi:10.1088/0963-0252/24/5/055003

Cited by 8 publications

(9 citation statements)

References 24 publications

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“…Recently, filaments have been observed in XUV images recorded during a modified plasma focus operation on the PF-1000 facility [100,127], when the plasma current sheath imploded on to a gas-puff injected axially and containing admixtures (in order to help visualization of the filaments). Some examples of XUV and interferometric images recorded at the PF-1000 facility with the deuterium filling and puffing are shown in Figure 19.…”

Section: Figure 16mentioning

confidence: 99%

“…(There is a possibility that this might be incorrectly evaluated: 750 eV may be the average photon energy and temperature may be~4 times less in line with other measurements). (3) Time integrated soft X-ray pinhole camera images [127] with the PF-1000 facility were compared for two modes of operation: normal mode and with gas puffing. The helical deviation of the boundary was discernible.…”

Section: Electronsmentioning

confidence: 99%

“…They are interpreted as being similar to spheromaks in magnetic topology. • Helical perturbations of the dense plasma column boundary are seen in soft X-ray, XUV and interferometry images [107,127,392]. They are potentially helical current flow paths that have both axial and azimuthal current components.…”

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confidence: 99%

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Update on the Scientific Status of the Plasma Focus

Auluck

Kubeš

Paduch

et al. 2021

Plasma

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This paper is a sequel to the 1998 review paper “Scientific status of the Dense Plasma Focus” with 16 authors belonging to 16 nations, whose initiative led to the establishment of the International Center for Dense Magnetized Plasmas (ICDMP) in the year 2000. Its focus is on understanding the principal defining characteristic features of the plasma focus in the light of the developments that have taken place in the last 20 years, in terms of new facilities, diagnostics, models, and insights. Although it is too soon to proclaim with certainty what the plasma focus phenomenon is, the results available to date conclusively indicate what it is demonstrably not. The review looks at the experimental data, cross-correlated across multiple diagnostics and multiple devices, to delineate the contours of an emerging narrative that is fascinatingly different from the standard narrative, which has guided the consensus in the plasma focus community for several decades, without invalidating it. It raises a question mark over the Fundamental Premise of Controlled Fusion Research, namely, that any fusion reaction having the character of a beam-target process must necessarily be more inefficient than a thermonuclear process with a confined thermal plasma at a suitably high temperature. Open questions that need attention of researchers are highlighted. A future course of action is suggested that individual plasma focus laboratories could adopt in order to positively influence the future growth of research in this field, to the general benefit of not only the controlled fusion research community but also the world at large.

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Section: Figure 16mentioning

confidence: 99%

Section: Electronsmentioning

confidence: 99%

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Update on the Scientific Status of the Plasma Focus

Auluck

Kubeš

Paduch

et al. 2021

Plasma

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“…It should also be noted that in different measuring channels, there were also recorded some narrow spikes corresponding to mono-energetic electron microbeams. The appearance of such microbeams could be explained by the acceleration of some electrons within tiny plasma diodes (formed probably near hot-spots), as described in our earlier papers [12,13] and in the introduction.…”

Section: Resultsmentioning

confidence: 81%

“…It can, however, be seen that for discharges with the krypton admixture more electron spikes were recorded and more distinct hot spots were observed. The number of the fast ion microbeams (recorded end-on by means of the ion pinhole camera) did not correspond exactly to the number of the visible hot spots, but not all plasma microdiodes might produce corresponding hot spots [13].…”

Section: Resultsmentioning

confidence: 93%

Measurements of fast electron beams and soft X-ray emission from plasma-focus experiments

et al. 2016

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Abstract. The paper reports results of the recent experimental studies of pulsed electron beams and soft X-rays in plasma-focus (PF) experiments carried out within a modifi ed PF-360U facility at the NCBJ, Poland. Particular attention was focused on time-resolved measurements of the fast electron beams by means of two different magnetic analyzers, which could record electrons of energy ranging from about 41 keV to about 715 keV in several (6 or 8) measuring channels. For discharges performed with the pure deuterium fi lling, many strong electron signals were recorded in all the measuring channels. Those signals were well correlated with the fi rst hard X-ray pulse detected by an external scintillation neutron-counter. In some of the analyzer channels, electron spikes (lasting about dozens of nanoseconds) and appearing in different instants after the current peculiarity (so-called current dip) were also recorded. For several discharges, fast ion beams, which were emitted along the z-axis and recorded with nuclear track detectors, were also investigated. Those measurements confi rmed a multibeam character of the ion emission. The time-integrated soft X-ray images, which were taken side-on by means of a pinhole camera and sensitive X-ray fi lms, showed the appearance of some fi lamentary structures and so-called hot spots. The application of small amounts of admixtures of different heavy noble gases, i.e. of argon (4.8% volumetric), krypton (1.6% volumetric), or xenon (0.8% volumetric), decreased intensity of the recorded electron beams, but increased intensity of the soft X-ray emission and showed more distinct and numerous hot spots. The recorded electron spikes have been explained as signals produced by quasi-mono-energetic microbeams emitted from tiny sources (probably plasma diodes), which can be formed near the observed hot spots.

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