Observations of Explosions of High-Speed Plasma in a Magnetic Field.
Winston H. Bostick
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In one page
Winston Bostick had already shown that his small plasma gun threw self-confining balls of plasma — plasmoids — across a magnetic field. Here, writing from the Stevens Institute of Technology about work done at the Livermore radiation laboratory, he asks a different question: what does a plasma explosion look like when it spreads out evenly around the field lines instead of being fired along them? The trick is simple. Fire the gun parallel to the field, then let the jet strike the apex of a cone, so the plasma scatters outward in the plane across the field. In a good vacuum the answer is sharp: the expanding plasma does not smear into a cloud, it breaks into three plasmoids that travel radially away. Fill the chamber with a thin conducting gas instead, and the same shot gives something else entirely — one irregular body trailing hairy prominences, which Bostick says is reminiscent of photographs of the Crab Nebula. Scale that up, he proposes, and you are watching a supernova.
Why it matters hereChapter 9 treats plasmoids as ordinary laboratory objects, and this note catches them forming by themselves out of an exploding plasma rather than being fired ready-made out of a gun. It also shows that the surrounding medium, not the gun, decides whether you get separate plasmoids or one ragged filamented body — and it is the site’s earliest statement of the method chapter 9 keeps returning to: build the astrophysical object on a bench, at the right scale, and photograph it.
What it claims
01The method. Bostick’s pulsed plasma gun projects plasma predominantly in the forward direction, so to obtain an explosion that is isotropic in the two dimensions perpendicular to a magnetic field he fires the plasma parallel to the field and scatters it off the apex of a conical barrier. That geometry converts a directed jet into a spreading explosion across the field lines.Page 237, opening paragraph, referring back to Physical Review 104, 292 (1956) and 106, 404 (1957)
Published and peer-reviewed02In a fairly good vacuum, about ten to the minus five millimetres of mercury, a time-exposure photograph of the process shows that the plasma breaks up into three plasmoids, which proceed radially outward. The explosion does not disperse: it partitions itself into a small number of discrete self-confined objects.Page 237, second paragraph
Published and peer-reviewed03Change the medium and the outcome changes. When the same process occurs inside a conducting medium, produced by photoionisation of the residual gas in the chamber at two microns pressure, the result is quite different: a time sequence of Kerr-cell shutter photographs shows the explosion producing an irregularly shaped body with hairy prominences instead of separate plasmoids.Page 237, third paragraph, with Figure 1
Published and peer-reviewed04Bostick’s own comparison for that filamented body is astronomical: it is somewhat reminiscent of the Crab Nebula photographed in the light of hydrogen-alpha. He is careful about the status of the comparison, calling these laboratory photographs the first crude efforts in this direction and noting that the photographic technique should be improved and that some fine structure is lost in the reproductions.Page 237, third and fourth paragraphs
Published and peer-reviewed05The programme he proposes is scaled laboratory astrophysics. Here, he writes, is a technique which through suitable similarity transformations may eventually yield interesting information on the dynamics of explosions of magnetic supernovae — the argument that a bench-top plasma, properly scaled, is a working model of an astrophysical one.Page 237, closing paragraph
What to watch
The way in
https://doi.org/10.1086/146455SOURCE READ IN FULL, TEXT NOT REPRODUCED. This is a one-page item in the Notes section of The Astrophysical Journal, volume 127, page 237, January 1958. The complete note was read for this sheet on 2026-09-08 from the free scan the NASA Astrophysics Data System serves at articles.adsabs.harvard.edu for bibcode 1958ApJ...127..237B, and every claim below is located to a passage of that page. The scan carries the line ‘© American Astronomical Society · Provided by the NASA Astrophysics Data System’ and no open licence was found for it, so no text of the note is reproduced here. Bibliography confirmed from Crossref: volume 127, page 237, January 1958. The note gives Bostick’s affiliation as the Stevens Institute of Technology, Hoboken, New Jersey, and its footnote states that the work was done under the auspices of the United States Atomic Energy Commission at the University of California Radiation Laboratory at Livermore. It cites only the author’s own two earlier papers, Physical Review 104, 292 (1956) and Physical Review 106, 404 (1957). Optical-character errors in the scan render the magnetic field as ‘magnetic held’ in places; pressures are given as about ten to the minus five millimetres of mercury and as two microns, and are quoted here in those terms.
How to cite it
Winston H. Bostick (1958) Observations of Explosions of High-Speed Plasma in a Magnetic Field.. doi:10.1086/146455
Where it sits in the curriculum