increase MPOL of VMEC input by one so that DESC eq has requisite reso…

[dpanici]

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…lution to capture shafranov shift

without this increase, the auto continuation solve from the command line yields an equilibrium with barely any shafranov shift

Things to check

• [ ] If the continuation method steps are weird or have changed
• [ ] if it is indeed the MPOL thing (MPOL to MPOL-1 upon loading VMEC was changed about 2 years ago, but 6 months ago we lowered the resolution from 12 to 8... so worth checking the code at that point)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 95.27%. Comparing base (87592bc) to head (874e4b0). Report is 1916 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1005   +/-   ##
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  Coverage   95.26%   95.27%           
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  Files          87       87           
  Lines       21719    21719           
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+ Hits        20691    20692    +1     
+ Misses       1028     1027    -1     

see 1 file with indirect coverage changes

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[dpanici]

I think the following files also have to be updated to stay self-consistent with this change:

• input.HELIOTRON_desc_no_continuation
• input.HELIOTRON_desc_no_continuation_output.h5
• basic_equilibrium.ipynb
• advanced_equilibrium_continuation.ipynb

the files that need updating have ben updated. The no continuation input does not need updating as the resolution was not changed for that one.

[f0uriest]

Feels really weird that going from m=8 to m=9 makes such a big difference?

[ddudt]

Feels really weird that going from m=8 to m=9 makes such a big difference?

@dpanici are you sure this PR is necessary? The notebooks on master look like they already have the correct Shafranov shift

[dpanici]

Feels really weird that going from m=8 to m=9 makes such a big difference?

@dpanici are you sure this PR is necessary? The notebooks on master look like they already have the correct Shafranov shift

Yea I am sure. If you rerun the examples on master, you completely lose the shafranov shift. Try it for yourself and see

[dpanici]

Feels really weird that going from m=8 to m=9 makes such a big difference?

I also agree but this is the result I see, if the point of the notebook is to just use the automatic contiunation that by default is used when running on a vmec input file, it currently results in an equilibrium with barely any shafranov shift on master after running python -m desc input.HELIOTRON

This is fixed if we up the resolution by 1. The current saved input.HELIOTRON_output.h5 on master has L=M=8 resolution, so possibly what happened is it is from before we made the change so that when we load a VMEC input file, we set MPOL to be one less than what VMEC's MPOL is

[f0uriest]

ok, im still a bit worried this is indicative of some larger issue. Can you check to see when it broke? Was it just because we changed the default m from vmec?

[dpanici]

Note to self, must make a new environment locally to load in older DESC versions

[dpanici]

make as an issue then merge this in @dpanici

[f0uriest]

Please clean up the pr title and description before merging