alexjrgreen wrote:Helium fluorescence lasts about 100 ns, so you're looking at a time slice.
Perhaps the fluorescence of a single heluim atom lasts a brief time, but the picture is a summation of many gazillions of fluorescing events spread out over time and area, only limited by the shutter speed of the camera ( and the confined volume of course. It says nothing about flows directly. Some assumptions can be applied for some qualitative conclusions.
I wonder, if the camera was positioned so hat a cusp was seen in crossection at right angles from it's origin, so that the proportions are not distorted, a graphic measurement could determine the realitive sizes of the cusp openings compared to the total surface area of the Wiffleball sphere. A comparison with a low electron current image could be enlightening. Comparing these images with electron gun currents, B-field strengths,potential, neutron production, etc could give results that validate predictions without more sophisticated plasma measurements.
In any case, some links concerning Wiffleballs:
http://www.askmar.com/Fusion_files/EMC2 ... eakage.pdf
http://www.askmar.com/Fusion_files/EMC2 ... lywell.pdf
http://www.askmar.com/ConferenceNotes/2 ... 0Paper.pdf
Page 4 of the last link . No details, but experimental evidence is claimed. Also, noted is a deemphasis on the critical importance of the Wiffleball from an energy balance perspective due to recirculation.
"Thus, all of the individual physics issues and effects required
to make the concept work HAVE been proven by the
extensive experimental tests made since 1994 in the EMC2
R&D program. These include:
- The WB cusp trapping effect (explained further below;
WB-2,3,4,5), its physics and numerical rates.
- The need for electron recirculation through all cusps of
the machine, so that cusp electron flow is not a loss
mechanism.
The consequent elimination of the WB trapping factor
as a measure of “losses“ it is simply a measure of
density ratios inside and outside the machine."
Dan Tibbets
To error is human... and I'm very human.