search

D3DEnergetic / FIDASIM

A Neutral Beam and Fast-ion Diagnostic Modeling Suite
http://d3denergetic.github.io/FIDASIM/
Other
27 stars 18 forks source link

definition of radius in NPA Geometry Structure #268

Closed rink2023 closed 9 months ago

rink2023 commented 9 months ago

I am confused on the definition of radius in NPA Geometry Structure. The instruction said the definition is: radius | Float64 | 1 | [nchan] | cm | Line of sight radius at midplane or tangency point I can not understand the exact meaning of "Line of sight radius at midplane or tangency point". Since the line of sight (LOS) coud be defined by two points a_cent and d_cent, why we still need radius to define the LOS.

regards

lstagner commented 9 months ago

You are correct. The radius field isn't actually necessary for the calculation of NPA flux. It is used when printing out information about the chords during runtime but thats it. You could just set it all to zero and it would be fine. Its there because most people associate channels with where they are looking in the machines so it gives them a way to internally visualize the channels.