Posted: Wed Mar 11, 2009 9:22 pm
Scupperer you're asking the right question IMO.
Having the nubs located at the mid-point along the edge of the inscribing cube of the Polywell is a mistake I think. If you take a look at this approx. spherical wiffleball (scroll down for colourful "beachball" picture with lines on it), one of the lowest field points is directly beneath a nub (radially speaking).
viewtopic.php?t=650&postdays=0&postorder=asc&start=30
It seems counterintuitive that a field low-point, i.e. the mid-edge cusp, should occur beneath where the coils come closest together, but I think this spherical solution is saying something about the way the field changes when the wiffleball forms and pushes back the magneto-static field.
Anyway, having the nub radially above a cusp is like putting it right in the firing line for oscillating (recirculating electrons). Moving it to a point either side would seem to make sense, quarter-point? or maybe three nubs spaced at 120 degrees?
I think there is also a question raised here about why the spacing of the closest point between the coils should be kept to the minimum (a couple of gyro-radii I think Bussard said). If these mid-edge cusp form when the wiffleball forms anyway, why not make the spacing between the coils at the edges something like the diameter of the coils themselves? This will make the strength of the all the cusps about equal and close up the central point cusps, that will be the largest source of losses in the current configuration. The way I see it, the present the magnetic "cage" is not spreading material optimally over the surface of the sphere it is trying to cover, a significant portion of it is doubling up near those mid-points.
Having the nubs located at the mid-point along the edge of the inscribing cube of the Polywell is a mistake I think. If you take a look at this approx. spherical wiffleball (scroll down for colourful "beachball" picture with lines on it), one of the lowest field points is directly beneath a nub (radially speaking).
viewtopic.php?t=650&postdays=0&postorder=asc&start=30
It seems counterintuitive that a field low-point, i.e. the mid-edge cusp, should occur beneath where the coils come closest together, but I think this spherical solution is saying something about the way the field changes when the wiffleball forms and pushes back the magneto-static field.
Anyway, having the nub radially above a cusp is like putting it right in the firing line for oscillating (recirculating electrons). Moving it to a point either side would seem to make sense, quarter-point? or maybe three nubs spaced at 120 degrees?
I think there is also a question raised here about why the spacing of the closest point between the coils should be kept to the minimum (a couple of gyro-radii I think Bussard said). If these mid-edge cusp form when the wiffleball forms anyway, why not make the spacing between the coils at the edges something like the diameter of the coils themselves? This will make the strength of the all the cusps about equal and close up the central point cusps, that will be the largest source of losses in the current configuration. The way I see it, the present the magnetic "cage" is not spreading material optimally over the surface of the sphere it is trying to cover, a significant portion of it is doubling up near those mid-points.