Fusion reaction profile plot_proc

[chris-ashe]

This pull request introduces fusion reaction rate profile tracking for multiple fusion channels and adds a new plotting function to visualize these profiles and their corresponding fusion power. The changes span data structure updates, calculation logic, and plotting enhancements, resulting in improved diagnostics and visualization of fusion rates and power across the plasma radius.

❇️ New variables

fusrat_plasma_dt_profile
fusrat_plasma_dd_helion_profile
fusrat_plasma_dhe3_profile
fusrat_plasma_dd_triton_profile

🎨 New output

Fusion Reaction Rate Profile Tracking and Visualization

Data Structure and Initialization:

• Added new variables to physics_variables.py to store plasma fusion reaction rate profiles for D-T, D-D (triton and helion branches), and D-3He channels, along with their initialization in init_physics_variables() and default values.
  Fusion Rate Profile Calculation:
• Each fusion reaction (D-T, D-D triton, D-D helion, D-3He) now computes and stores its radial fusion rate profile in the corresponding variable using the Bosch-Hale reactivity and plasma profiles.
  Plotting Enhancements:
• Implemented plot_fusion_rate_profiles() in plot_proc.py to visualize fusion rate and fusion power profiles for all channels, with detailed annotations and legends for diagnostics.
• Integrated the new plot into the main plotting routine and output PDF, including figure creation, subplot assignment, and proper closing of resources.

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 10.05291% with 170 lines in your changes missing coverage. Please review.
✅ Project coverage is 44.77%. Comparing base (68d8058) to head (2a0fef5).
⚠️ Report is 21 commits behind head on main.

Files with missing lines	Patch %	Lines
process/io/plot_proc.py	1.96%	150 Missing ⚠️
process/physics.py	5.88%	16 Missing ⚠️
process/fusion_reactions.py	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3827      +/-   ##
==========================================
- Coverage   46.67%   44.77%   -1.91%     
==========================================
  Files         122      122              
  Lines       27804    30481    +2677     
==========================================
+ Hits        12977    13647     +670     
- Misses      14827    16834    +2007     

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[jonmaddock]

I don't like all these hardcoded numbers that need moving around. Fine here, but can you make an issue to turn this into a list?

[jonmaddock]

Seems like regression tests are failing due to request limits. Can you re-run or talk to Tim about how we can work around these?

[j-a-foster]

Happy with the changes.