4165 new energy confinement scaling for ncst spherical tokamak

[grmtrkngtn]

Description

Adds new NCST confinement time scaling law.

Checklist

I confirm that I have completed the following checks:

• My changes follow the PROCESS style guide
• I have justified any large differences in the regression tests caused by this pull request in the comments.
• I have added new tests where appropriate for the changes I have made.
• If I have had to change any existing unit or integration tests, I have justified this change in the pull request comments.
• If I have made documentation changes, I have checked they render correctly.
• I have added documentation for my change, if appropriate.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 66.66667% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 48.66%. Comparing base (cdccae0) to head (4587820).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
process/models/physics/confinement_time.py	60.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4480      +/-   ##
==========================================
+ Coverage   48.65%   48.66%   +0.01%     
==========================================
  Files         151      151              
  Lines       29714    29731      +17     
==========================================
+ Hits        14457    14469      +12     
- Misses      15257    15262       +5     

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[chris-ashe]

@grmtrkngtn A documentation addition still needs to be done also

[chris-ashe]

Suggested change

	pcur: float,
	cur_plasma_ma: float,

I know lots of the scaling still say pcur but cur_plasma_ma is the current correct style guide way

[grmtrkngtn]

Per Alex's comment, maybe it's best to leave these for now and resolve the file in totality.

[chris-ashe]

Should we not then be using the pedestal or the separatrix density then?

[grmtrkngtn]

I'm not sure pedestal is a good choice given this is for L-mode plasmas. Besides, its numerical effect is very small because the fitted exponent is only -0.01

[ajpearcey]

I would note, that this will cause a lot of conflicts with #4386 which is also trying to add in a scaling number 51. with several of the same name changes made.

I would also note that all the code has currents and current fraction with variables names like f_c_plasma_bootstrap, f_c_plasma_auxiliary, f_c_plasma_inductive. I personally think changing some subsections of the current variable names and leaving other is confusing. I'd spin this part out into it's own PR.