davidl@tekig5.UUCP (David Levadie) (03/27/85)
I'm sure this subject has been beaten to death in here, but it didn't happen on my watch, so... Is there any physics explaining ball lightening? (I've heard NO from a variety of sources). Somebody recently claimed that Maxwell's equations won't allow for a spherical electromagnetic field, though they weren't very explicit. More recently I heard that someone has begun research into ball lightening as a possible containment mechanism for nuclear fusion, an idea whiich occured to me some time ago. This person claims that an explanation could be derived from postulating a toroidal plasma with a currrent circulating helically around the toroid. the claim was that Tokamak generators use such a field to create the "magnetic bottle" for plasma containment. Supposedly, somebody is doing 3D field modeling to explore this, using a Cray somethingorother. ?
gwyn@brl-tgr.ARPA (Doug Gwyn <gwyn>) (03/29/85)
> ... Somebody recently claimed that Maxwell's equations > won't allow for a spherical electromagnetic field ... This doesn't appear to have anything to do with ball lightning, though. One does not see the field, but rather ionization paths of the air. > ... a possible containment mechanism for > nuclear fusion ... The problem really is that plasma is inherently unstable; its natural tendency is to undergo oscillations. Trying to contain plasma for very long seems to be fighting Mother Nature. How about working on a continuous-flow process? Get some top-notch chemical engineers in on the system design. This reminds me of Robert Goddard's WWI rockets, which injected a sequence of solid-fuel pellets into the combustion chamber. He later caught onto the idea of liquid propellant and radically altered the nature of rocketry thereby. Perhaps the fusion-via- pellet-implosion people should think about this..
pmk@prometheus.UUCP (Paul M Koloc) (04/03/85)
> One does not see the field, but rather ionization paths of the air. There is a photograph of ball lightning that clearly shows evidence of a dipole field slightly poking out of the surface by its effect on the plasma transport. (The sun too, during full solar eclipse). In other regions, the transport is clamped by the tangentially trapped magnetic poloidal flux surface. Consequently, the polar areas show a sort of "fluffiness" while the other areas show a sharp and smooth edge. In fact the fluffiness of the uppermost polar region shows erosion from convective currents. The consequence of this is that the damn thing must have been there at least a couple of seconds for this process to have come into full effect. > ... as possible containment mechanism for nuclear fusion ... > The problem really is that plasma is inherently unstable; > its natural tendency is to undergo oscillations. Actually, oscillations don't make the system "unstable" unless they grow in amplitude without bound (or beyond the containment's ability to hold the plasma together). Oscillations can be be kept within bounds easily by operating the system in its minimum energy configuration, using sheer, etc. Since the confinement schemes for fusion and "ball lightning" contain magnetic fields, generating sheered field surfaces (rotation of one surface with respect to the other) will cause the return oscillatory wave to be displaced spatially, (walk). As long as this displacement has a long repeat path, the oscillatory waves will not grow rapidly. Adjacent surfaces oscillate in different directions so that the bulk plasma is dispersive. > Trying to contain plasma for very long seems to be fighting > Mother Nature. What? There is such a paucity of plasma in existence that isn't "contained" by "Mother Nature" that this is actually kind of a funny thing to say, i. e. ball lightnings are stable, as are stars. In fact fighting nature by "constraining " the plasma from finding its minimum energy state, is "fighting nature". We fortunately have a half billion $ a year program at DOE Office of Fusion (Confusion) Energy to do that for us. And they do it well with every possible effort. When they find one that does it well they really get busy, i.e. tokamaks and mirror. Don't be a sap!!! Physics is the biggest collection of half baked "understandings" that has ever existed. And, "plasma physics ???" . .. come on they haven't even scratched the surface of understanding, for a "science" it has NOT been around long enough for them to be able to cut the umbilical cord. When I was a kid these arrogant bastards (lacking one parental unit during childhood) laughingly referred to Aristole as a "crack pot" because he suggested " four elements ---- earth, water, air, and fire", and ha ha ha !! we know of 92 (naturally occurring) elements. Didn't occur to them he was discussing "states of matter"--- solid, liquid, gas, and plasma These jerks thought the sun was composed of a "very hot gas". Bye for now. Paul Just enjoying needling the "taking of P H Y S I C S too seriously". +-------------------------------------------------------+--------+ | pmk@prometheus: (301) 445-1075 | FUSION | | Prometheus II Ltd., College Park, MD 20740-0222 | this | | ..!{umcp-cs,seismo}!prometh!pmk | decade | +-------------------------------------------------------+--------+ -- |-------------------------------------------------------|--------| | pmk@prometheus: (301) 445-1075 | FUSION | | Prometheus II Ltd., College Park, MD 20740-0222 | this | | ..!{umcp-cs,seismo}!prometh!pmk | decade | |-------------------------------------------------------|--------|
ethan@utastro.UUCP (Ethan Vishniac) (04/04/85)
> > > Trying to contain plasma for very long seems to be fighting > > Mother Nature. > > What? There is such a paucity of plasma in existence that isn't > "contained" by "Mother Nature" that this is actually kind of > a funny thing to say, i. e. ball lightnings are stable, as are > stars. In fact fighting nature by "constraining " the plasma > from finding its minimum energy state, is "fighting nature". We > fortunately have a half billion $ a year program at DOE Office of > Fusion (Confusion) Energy to do that for us. And they do it well > with every possible effort. When they find one that does it well > they really get busy, i.e. tokamaks and mirror. Let's not be unduly harsh. Stars are contained by their own gravity. Clearly one cannot contain a Tokomak plasma that way. There is a theorem which states that pure plasma cannot confine itself with self-generated fields. It's a good theorem. The explanation you gave for ball lightning seemed to get around it by considering the external pressure (from the air) as well as the internal fields. [Incidentally, I never heard this explanation before. Can you give a reference?] I have met people so impressed by the evident force of that theorem that they have insisted that ball lightning is a fluorescence phenomenon with little internal energy. This is a little odd since I believe there is at least one historical account of a death caused by coming into contact with ball lightning. Note that the person who told me this was an expert on lightning. He was giving a colloquium at Fermilab. "Don't argue with a fool. Ethan Vishniac Borrow his money." {charm,ut-sally,ut-ngp,noao}!utastro!ethan Department of Astronomy University of Texas
bill@utastro.UUCP (William H. Jefferys) (04/05/85)
> This is a little > odd since I believe there is at least one historical account of a death > caused by coming into contact with ball lightning. > Which reminds me of a story whose source I have forgotten. It may even be true. A husband and wife were sitting on the front porch during a storm, and ball lightning was formed. The ball lightning moved across the lawn and over to the porch door where it dissipated itself with a loud bang on the screen, immolating a fly in the process. The wife (she must have been a Vermonter) without batting an eye remarked, "Sure got that fly that time, Henry!" -- "Men never do evil so cheerfully and so completely as when they do so from religious conviction." -- Blaise Pascal Bill Jefferys 8-% Astronomy Dept, University of Texas, Austin TX 78712 (USnail) {allegra,ihnp4}!{ut-sally,noao}!utastro!bill (uucp) bill%utastro.UTEXAS@ut-sally.ARPA (ARPANET)