Talk-Polywell.org

rnebel wrote on another thread,

The alphas make about 1000 passes before they exit through the cusps. They leave at essentially full energy.

And also -

Loss fraction = (summation (pi*rl**2))/(4*pi*R**2) where rl is the electron gyroradius and R is the coil radius. The summation is a summation over each of the point cusps. If you calculate rl from one of the coil faces, then there are "effectively" ~ 10 point cusps (fields are larger in the corners than the faces). The factor that your observed confinement exceeds this model is then lumped together as the cusp recycle factor.

The other model is ...

Consider a 100 Mw net power device, that is, about 140 Mw gross power. (Please feel free to adjust my numbers where needed) Does that mean that each of the cusps will see 14 MVA of power flow out? That's a pretty hefty current. Will it create its own B field and potentially disrupt cusp confinement? Or will it reinforce? (I can hope.)

Taking output potential as 1.2MV that is only about 12A.

Aero: Is there a standard definition for what is a "Loss fraction"?

Is it simply the ratio of output power, P_o, to input power, P_i, i.e. Q?

For example if the fusion output power, is scaling like

P_o = k_o * B^4 * R^3

where B - magnetic field strength, R - major radius of the coils, k_o some constant of proportionality and the formula for the "Loss fraction" is that given above by Rick N., what exactly does that mean for the scaling of

Q = P_o/P_i

as function of B, R, k_o, rl where rl -is electron gyroradius Rick N. uses above.

Anyone like to spell out the functionality for Q(B,R,k_o,rl) for the slower amongst us?

icarus wrote:Aero: Is there a standard definition for what is a "Loss fraction"?

Is it simply the ratio of input power, P_i, to output power, P_o, i.e. Q?

For example if the fusion output power, is scaling like

P_o = k_o * B^4 * R^3

where B - magnetic field strength, R - major radius of the coils, k_o some constant of proportionality and the formula for the "Loss fraction" is that given above by Rick N., what exactly does that mean for the scaling of

Q = P_i/P_o

as function of B, R, k_o, rl where rl -is electron gyroradius Rick N. uses above.

Anyone like to spell out the functionality for Q(B,R,k_o,rl) for the slower amongst us?

I expect there is a basic definition of a loss fraction in general and someone on this forum knows what it is. It may or may not be the obvious, like
loss fraction = loss/total.
However, I did find an interesting paper.
http://www.nifs.ac.jp/report/annrep07/pdf/272.pdf
Of course, for our purposes, we need to use the formula that Rick provided.