Create plasma current class by chris-ashe · Pull Request #4086 · ukaea/PROCESS

chris-ashe · 2026-02-08T22:09:11Z

This pull request introduces significant improvements to how plasma current is modeled, calculated, and visualized throughout the codebase and documentation. It refactors the plasma current logic into a dedicated PlasmaCurrent class, updates the documentation for clarity and accuracy, expands the set of tracked plasma current variables, and adapts plotting and testing to use the new structure.

Key changes include:

Refactoring and Integration of Plasma Current Calculations:

Introduced the new PlasmaCurrent class, centralizing all plasma current calculations, and integrated it throughout the codebase, including in the main application logic (process/main.py), plotting (process/core/io/plot_proc.py), and unit tests (tests/unit/test_physics.py).

Enhancements to Data Structure:

Expanded physics_variables to include a comprehensive set of plasma current calculation results from different empirical and analytic models, with initialization and documentation for each new variable.

Documentation Improvements:

Updated and clarified the plasma current documentation, including correcting equations to use consistent physical constants, refining explanations, and adding explicit references to calculation functions.

Plotting Updates:

Modified the main plotting routine to use the new plasma current comparison plot from PlasmaCurrent, adjusted subplot indexing to accommodate new plots, and increased the number of figure pages accordingly.

Testing Adaptation:

Refactored plasma current-related unit tests to use the new PlasmaCurrent class and removed outdated test parameters and checks, ensuring alignment with the updated calculation interface.

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 · 2026-02-08T22:18:00Z

Codecov Report

❌ Patch coverage is 53.69650% with 119 lines in your changes missing coverage. Please review.
✅ Project coverage is 47.97%. Comparing base (c9a2074) to head (92b344d).

Files with missing lines	Patch %	Lines
process/models/physics/plasma_current.py	56.68%	81 Missing ⚠️
process/core/io/plot_proc.py	2.94%	33 Missing ⚠️
process/models/physics/physics.py	28.57%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4086      +/-   ##
==========================================
+ Coverage   47.84%   47.97%   +0.12%     
==========================================
  Files         141      142       +1     
  Lines       29754    29883     +129     
==========================================
+ Hits        14236    14335      +99     
- Misses      15518    15548      +30

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

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❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

…dels

- Updated test_physics.py to instantiate PlasmaCurrent for calculating plasma current and related methods. - Replaced direct calls to calculate_plasma_current_peng and calculate_current_coefficient_hastie with PlasmaCurrent class methods. - Modified test_stellarator.py to include PlasmaCurrent in the stellarator setup.

…r improved readability and maintainability

…ed clarity and maintainability

…ated tests for consistency

…rrent class

…calculations in PlasmaCurrent class

…PlasmaCurrent class

…curacy

…lot_proc and update data structure in PlasmaCurrent class

timothy-nunn

There are an awful many changes in the conventional aspect ratio cases, I suspect there is a big somewhere

2026-03-19T15:48:41.5813756Z FAILED tests/regression/test_process_input_files.py::test_input_file[large_tokamak_nof] - AssertionError: �[0;32m 8593 differences: the reference MFile contains different values for some of the variables. See the warnings for a breakdown of the differences.�[0m
2026-03-19T15:48:41.5813858Z assert 8593 == 0
2026-03-19T15:48:41.5815860Z  +  where 8593 = len([MFileVariableDifference(name='pfc1t4', ref=287728.4430610426, new=-2272946.4289503414, percentage_change=-889.962370341026), MFileVariableDifference(name='i_plasma_current', ref=4.0, new=9.0, percentage_change=125.0), MFileVariableDifference(name='f_c_plasma_hcd_primary', ref=0.027082630195024323, new=0.0, percentage_change=-100.0), MFileVariableDifference(name='f_c_plasma_auxiliary', ref=0.027082630195024326, new=0.0, percentage_change=-100.0), MFileVariableDifference(name='c_hcd_primary_driven', ref=453313.9488936291, new=0.0, percentage_change=-100.0), MFileVariableDifference(name='p_hcd_injected_current_total_mw', ref=9.81398334505902, new=0.0, percentage_change=-100.0), ...])
2026-03-19T15:48:41.5816768Z FAILED tests/regression/test_process_input_files.py::test_input_file[large_tokamak_eval] - AssertionError: �[0;32m 8614 differences: the reference MFile contains different values for some of the variables. See the warnings for a breakdown of the differences.�[0m
2026-03-19T15:48:41.5816850Z assert 8614 == 0
2026-03-19T15:48:41.5818785Z  +  where 8614 = len([MFileVariableDifference(name='pfc0t4', ref=-543745.9921847769, new=-2804442.4944127165, percentage_change=-415.7633407364417), MFileVariableDifference(name='i_plasma_current', ref=4.0, new=9.0, percentage_change=125.0), MFileVariableDifference(name='f_c_plasma_hcd_primary', ref=0.010312341172393658, new=0.0, percentage_change=-100.0), MFileVariableDifference(name='f_c_plasma_auxiliary', ref=0.010312341172393658, new=0.0, percentage_change=-100.0), MFileVariableDifference(name='c_hcd_primary_driven', ref=165936.8656852688, new=0.0, percentage_change=-100.0), MFileVariableDifference(name='p_hcd_injected_current_total_mw', ref=3.413518735361287, new=0.0, percentage_change=-100.0), ...])
2026-03-19T15:48:41.5819795Z FAILED tests/regression/test_process_input_files.py::test_input_file[low_aspect_ratio_DEMO] - AssertionError: �[0;32m 7988 differences: the reference MFile contains different values for some of the variables. See the warnings for a breakdown of the differences.�[0m
2026-03-19T15:48:41.5819868Z assert 7988 == 0
2026-03-19T15:48:41.5822069Z  +  where 7988 = len([MFileVariableDifference(name='pfc1t4', ref=-66468.16490802169, new=-2160158.9627523157, percentage_change=-3149.915152225931), MFileVariableDifference(name='cs_t3', ref=8023669.20057866, new=37198927.57899087, percentage_change=363.6149204195521), MFileVariableDifference(name='cs_t2', ref=8023669.20057866, new=37198927.57899087, percentage_change=363.6149204195521), MFileVariableDifference(name='f_j_cs_start_end_flat_top', ref=-0.04323663015144943, new=-0.20045146846873732, percentage_change=-363.6149204195497), MFileVariableDifference(name='big_q_plasma', ref=33.05921861558781, new=95.42180776169131, percentage_change=188.63902946786166), MFileVariableDifference(name='i_plasma_current', ref=4.0, new=9.0, percentage_change=125.0), ...])

timothy-nunn · 2026-03-19T14:18:32Z

documentation/source/physics-models/plasma_current/plasma_current.md

Can you get someone to check the formula changes here

timothy-nunn · 2026-03-19T14:20:47Z

tests/unit/test_physics.py

-            expected_bp=0.96008591022564971,
-            expected_qstar=2.900802902105021,


Any way of making another test that checks these calculations are still correct?

timothy-nunn · 2026-03-19T14:22:01Z

process/models/physics/physics.py

+        Triangularity at 95% of the plasma boundary.
+    Returns
+    -------
+    float


Suggested change

Triangularity at 95% of the plasma boundary.

Returns

-------

float

Triangularity at 95% of the plasma boundary.

Returns

-------

float

timothy-nunn · 2026-03-19T14:22:21Z

process/models/physics/physics.py

+        Cylindrical safety factor (dimensionless).
+    Notes


Suggested change

Cylindrical safety factor (dimensionless).

Notes

Cylindrical safety factor (dimensionless).

Notes

timothy-nunn · 2026-03-19T16:16:57Z

process/models/physics/physics.py

                    po.ovarrf(
                        self.outfile,
-                        "Current density profile factor",
+                        "\nCurrent density profile factor",


This strikes me as something that will cause problems in the MFile. What is the purpose anyway?

timothy-nunn · 2026-03-19T16:18:21Z

process/models/physics/physics.py

 logger = logging.getLogger(__name__)


+def calculate_cylindrical_safety_factor(


Could probably be jit'ed

timothy-nunn · 2026-03-19T16:21:26Z

process/models/physics/plasma_current.py

+        except ValueError:
+            raise ProcessValueError(
+                "Illegal value of i_plasma_current",
+                i_plasma_current=physics_variables.i_plasma_current,
+            ) from None


Suggested change

except ValueError:

raise ProcessValueError(

"Illegal value of i_plasma_current",

i_plasma_current=physics_variables.i_plasma_current,

) from None

except ValueError as e:

raise ProcessValueError(

"Illegal value of i_plasma_current",

i_plasma_current=physics_variables.i_plasma_current,

) from e

timothy-nunn · 2026-03-19T16:22:32Z

process/models/physics/plasma_current.py

+        physics_variables.c_plasma_peng_analytic = plasma_currents.get(
+            PlasmaCurrentModel.PENG_ANALYTIC_FIT
+        )
+        physics_variables.c_plasma_peng_double_null = plasma_currents.get(
+            PlasmaCurrentModel.PENG_DIVERTOR_SCALING
+        )
+        physics_variables.c_plasma_cyclindrical = plasma_currents.get(
+            PlasmaCurrentModel.ITER_SCALING
+        )
+        physics_variables.c_plasma_ipdg89 = plasma_currents.get(
+            PlasmaCurrentModel.IPDG89_SCALING
+        )
+        physics_variables.c_plasma_todd_empirical_i = plasma_currents.get(
+            PlasmaCurrentModel.TODD_EMPIRICAL_SCALING_I
+        )
+        physics_variables.c_plasma_todd_empirical_ii = plasma_currents.get(
+            PlasmaCurrentModel.TODD_EMPIRICAL_SCALING_II
+        )
+        physics_variables.c_plasma_connor_hastie = plasma_currents.get(
+            PlasmaCurrentModel.CONNOR_HASTIE_MODEL
+        )
+        physics_variables.c_plasma_sauter = plasma_currents.get(
+            PlasmaCurrentModel.SAUTER_SCALING
+        )
+        physics_variables.c_plasma_fiesta_st = plasma_currents.get(
+            PlasmaCurrentModel.FIESTA_ST_SCALING
+        )


If these are only being calculated in output_plasma_current_models is it required to create new variables to hold their values? Surely these new variables won't be used anywhere else in the code

chris-ashe added Physics Relating to the physics models Refactor labels Feb 8, 2026

chris-ashe force-pushed the create_plasma_current_class branch from 935e8f0 to 660cc7c Compare February 26, 2026 15:00

chris-ashe force-pushed the create_plasma_current_class branch from 248115d to 632de11 Compare March 6, 2026 14:33

chris-ashe marked this pull request as ready for review March 16, 2026 11:46

chris-ashe requested a review from a team as a code owner March 16, 2026 11:46

timothy-nunn self-assigned this Mar 16, 2026

chris-ashe added 16 commits March 19, 2026 15:40

Add PlasmaCurrent class and integrate into Physics and Stellarator mo…

1fb1dc3

…dels

Create plasma current class

da0c636

Add cylindrical safety factor calculation to Physics model

26eb5aa

Fix import statements in plasma_current.py for consistency

484a4eb

Add cylindrical plasma current calculation method to PlasmaCurrent class

4de76c4

Refactor plasma current calculation to use PlasmaCurrentModel enum fo…

9476a63

…r improved readability and maintainability

❇️ Add additional plasma current variables to physics_variables module

b3c2667

Refactor plasma current calculations and update unit tests for improv…

07f7b92

…ed clarity and maintainability

Remove unused rmu0 parameter from plasma current calculations and rel…

524aed3

…ated tests for consistency

Add output method for plasma current models and update calculations

269983a

Add plotting functionality for plasma current comparisons in PlasmaCu…

8fea553

…rrent class

Refactor PlasmaCurrentModel to include full names and update related …

8ca413d

…calculations in PlasmaCurrent class

Update plasma_current documentation and remove unused parameter from …

34370b6

…PlasmaCurrent class

🐛 Fix Todd scaling calculation in PlasmaCurrent class for improved ac…

58bee19

…curacy

Enhance plasma current information display with full model names in p…

92b344d

…lot_proc and update data structure in PlasmaCurrent class

chris-ashe force-pushed the create_plasma_current_class branch from 539add7 to 92b344d Compare March 19, 2026 15:42

timothy-nunn requested changes Mar 19, 2026

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Create plasma current class#4086

Create plasma current class#4086
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create_plasma_current_class

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		expected_bp=0.96008591022564971,
		expected_qstar=2.900802902105021,

		logger = logging.getLogger(__name__)


		def calculate_cylindrical_safety_factor(

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chris-ashe commented Feb 8, 2026 •

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