diff --git a/examples/single_model_evaluation.ex.py b/examples/single_model_evaluation.ex.py
index 18fa0506a1..c873a99d28 100644
--- a/examples/single_model_evaluation.ex.py
+++ b/examples/single_model_evaluation.ex.py
@@ -58,8 +58,7 @@
 def print_values():
     """Function to print values of some variables"""
     print(
-        "W frac = "
-        f"{single_run.data.impurity_radiation.f_nd_impurity_electron_array[13]:.3e}"
+        f"W frac = {single_run.data.impurity_radiation.f_nd_impurity_electrons[13]:.3e}"
     )
     print(f"p_plasma_rad_mw = {single_run.data.physics.p_plasma_rad_mw:.3e}")
     print(
@@ -74,7 +73,7 @@ def print_values():
 # the divertor power.
 
 # %%
-single_run.data.impurity_radiation.f_nd_impurity_electron_array[13] = 5.0e-5
+single_run.data.impurity_radiation.f_nd_impurity_electrons[13] = 5.0e-5
 single_run.models.physics.run()
 print_values()
 
@@ -101,7 +100,7 @@ def run_impurities(w_imp_fracs):
     # Loop over W impurity values, evaluate model and store responses at each point
     for i, imp_frac in enumerate(w_imp_fracs):
         # Set W impurity fraction, then run physics model
-        single_run.data.impurity_radiation.f_nd_impurity_electron_array[13] = imp_frac
+        single_run.data.impurity_radiation.f_nd_impurity_electrons[13] = imp_frac
         single_run.models.physics.run()
 
         # Evaluate constraint equation 15 (L-H threshold constraint)
diff --git a/process/core/init.py b/process/core/init.py
index 4b5b537029..16165d9ac6 100644
--- a/process/core/init.py
+++ b/process/core/init.py
@@ -23,7 +23,6 @@
     InboardBlanketConfiguration,
     TFCSRadialConfiguration,
 )
-from process.data_structure.impurity_radiation_variables import N_IMPURITIES
 from process.data_structure.numerics import FiguresOfMerit, PROCESSRunMode
 from process.data_structure.pfcoil_variables import PFConductorModel
 from process.data_structure.physics_variables import (
@@ -409,12 +408,6 @@ def check_process(inputs, data):  # noqa: ARG001
             " or set to the default value 0.1D0."
         )
 
-    # Impurity fractions
-    for imp in range(N_IMPURITIES):
-        data.impurity_radiation.f_nd_impurity_electron_array[imp] = (
-            data.impurity_radiation.f_nd_impurity_electrons[imp]
-        )
-
     # Stop the run if j_tf_coil_full_area is used as an optimisation variable
     # As the current density is now calculated from b_plasma_toroidal_on_axis
     # without constraint 10
diff --git a/process/core/scan.py b/process/core/scan.py
index 436416368c..99dba07e61 100644
--- a/process/core/scan.py
+++ b/process/core/scan.py
@@ -105,8 +105,6 @@ def set(self, data: DataStructure, sweep_val: float):
         if "__" in self.name:
             name, index = self.name.split("__")
             getattr(var_area, name)[int(index) - 1] = sweep_val
-            if name == "f_nd_impurity_electrons":
-                var_area.f_nd_impurity_electron_array[int(index - 1)] = sweep_val
         else:
             setattr(var_area, self.name, sweep_val)
             name = self.name
diff --git a/process/core/solver/iteration_variables.py b/process/core/solver/iteration_variables.py
index 5b18d680a6..09a8a7fb59 100644
--- a/process/core/solver/iteration_variables.py
+++ b/process/core/solver/iteration_variables.py
@@ -108,7 +108,7 @@ class IterationVariable:
         "impurity_radiation",
         1e-8,
         0.01,
-        target_name="f_nd_impurity_electron_array",
+        target_name="f_nd_impurity_electrons",
         array_index=2,
     ),
     126: IterationVariable(
@@ -116,7 +116,7 @@ class IterationVariable:
         "impurity_radiation",
         1e-8,
         0.01,
-        target_name="f_nd_impurity_electron_array",
+        target_name="f_nd_impurity_electrons",
         array_index=3,
     ),
     127: IterationVariable(
@@ -124,7 +124,7 @@ class IterationVariable:
         "impurity_radiation",
         1e-8,
         0.01,
-        target_name="f_nd_impurity_electron_array",
+        target_name="f_nd_impurity_electrons",
         array_index=4,
     ),
     128: IterationVariable(
@@ -132,7 +132,7 @@ class IterationVariable:
         "impurity_radiation",
         1e-8,
         0.01,
-        target_name="f_nd_impurity_electron_array",
+        target_name="f_nd_impurity_electrons",
         array_index=5,
     ),
     129: IterationVariable(
@@ -140,7 +140,7 @@ class IterationVariable:
         "impurity_radiation",
         1e-8,
         0.01,
-        target_name="f_nd_impurity_electron_array",
+        target_name="f_nd_impurity_electrons",
         array_index=6,
     ),
     130: IterationVariable(
@@ -148,7 +148,7 @@ class IterationVariable:
         "impurity_radiation",
         1e-8,
         0.01,
-        target_name="f_nd_impurity_electron_array",
+        target_name="f_nd_impurity_electrons",
         array_index=7,
     ),
     131: IterationVariable(
@@ -156,7 +156,7 @@ class IterationVariable:
         "impurity_radiation",
         1e-8,
         0.01,
-        target_name="f_nd_impurity_electron_array",
+        target_name="f_nd_impurity_electrons",
         array_index=8,
     ),
     132: IterationVariable(
@@ -164,7 +164,7 @@ class IterationVariable:
         "impurity_radiation",
         1e-8,
         0.01,
-        target_name="f_nd_impurity_electron_array",
+        target_name="f_nd_impurity_electrons",
         array_index=9,
     ),
     133: IterationVariable(
@@ -172,7 +172,7 @@ class IterationVariable:
         "impurity_radiation",
         1e-8,
         0.01,
-        target_name="f_nd_impurity_electron_array",
+        target_name="f_nd_impurity_electrons",
         array_index=10,
     ),
     134: IterationVariable(
@@ -180,7 +180,7 @@ class IterationVariable:
         "impurity_radiation",
         1e-8,
         0.01,
-        target_name="f_nd_impurity_electron_array",
+        target_name="f_nd_impurity_electrons",
         array_index=11,
     ),
     135: IterationVariable(
@@ -188,7 +188,7 @@ class IterationVariable:
         "impurity_radiation",
         1e-8,
         0.01,
-        target_name="f_nd_impurity_electron_array",
+        target_name="f_nd_impurity_electrons",
         array_index=12,
     ),
     136: IterationVariable(
@@ -196,7 +196,7 @@ class IterationVariable:
         "impurity_radiation",
         1e-8,
         0.01,
-        target_name="f_nd_impurity_electron_array",
+        target_name="f_nd_impurity_electrons",
         array_index=13,
     ),
     138: IterationVariable(
diff --git a/process/data_structure/impurity_radiation_variables.py b/process/data_structure/impurity_radiation_variables.py
index d1992a0145..674b684092 100644
--- a/process/data_structure/impurity_radiation_variables.py
+++ b/process/data_structure/impurity_radiation_variables.py
@@ -104,11 +104,6 @@ class ImpurityRadiationData:
     )
     """Full ion charge of impurity species"""
 
-    impurity_arr_label: list[str] = field(
-        default_factory=lambda: np.full(N_IMPURITIES, "  ")
-    )
-    """Array of impurity labels for internal use"""
-
     impurity_arr_z: list[float] = field(default_factory=lambda: np.zeros(N_IMPURITIES))
 
     m_impurity_amu_array: list[float] = field(
@@ -116,11 +111,6 @@ class ImpurityRadiationData:
     )
     """2D array of impurity atomic masses in Atomic Mass Units (amu)"""
 
-    f_nd_impurity_electron_array: list[float] = field(
-        default_factory=lambda: np.zeros(N_IMPURITIES)
-    )
-    """2D array of impurity relative densities (n_imp/n_e)"""
-
     impurity_arr_len_tab: list[int] = field(
         default_factory=lambda: np.full(N_IMPURITIES, 0)
     )
diff --git a/process/models/physics/impurity_radiation.py b/process/models/physics/impurity_radiation.py
index b89e0a746d..767a3f57a7 100644
--- a/process/models/physics/impurity_radiation.py
+++ b/process/models/physics/impurity_radiation.py
@@ -54,30 +54,22 @@ def initialise_imprad(data: DataStructure):
     """
     errorflag = 0
 
-    f_nd_species_electron = 1.0e0
-
     #  Hydrogen
-
     init_imp_element(
         n_species_index=1,
         name_label=data.impurity_radiation.imp_label[0],
         z=1,
         m_species_amu=constants.M_PROTIUM_AMU,  # 1.00782503223 1H
-        f_nd_species_electron=f_nd_species_electron,
         len_tab=N_IMPURITIY_LOSS_FUNCTION_POINTS,
         error=errorflag,
         data=data,
     )
-
-    f_nd_species_electron = 0.0e0
-
     #  Helium
     init_imp_element(
         n_species_index=2,
         name_label=data.impurity_radiation.imp_label[1],
         z=2,
         m_species_amu=constants.M_HELIUM_AMU,  # 4.002602 (3He,4He) Average mass
-        f_nd_species_electron=f_nd_species_electron,
         len_tab=N_IMPURITIY_LOSS_FUNCTION_POINTS,
         error=errorflag,
         data=data,
@@ -89,7 +81,6 @@ def initialise_imprad(data: DataStructure):
         name_label=data.impurity_radiation.imp_label[2],
         z=4,
         m_species_amu=constants.M_BERYLLIUM_AMU,  # 9.0121831 9Be
-        f_nd_species_electron=f_nd_species_electron,
         len_tab=N_IMPURITIY_LOSS_FUNCTION_POINTS,
         error=errorflag,
         data=data,
@@ -101,7 +92,6 @@ def initialise_imprad(data: DataStructure):
         name_label=data.impurity_radiation.imp_label[3],
         z=6,
         m_species_amu=constants.M_CARBON_AMU,  # 12.0096, (12C,13C,14C) Average mass
-        f_nd_species_electron=f_nd_species_electron,
         len_tab=N_IMPURITIY_LOSS_FUNCTION_POINTS,
         error=errorflag,
         data=data,
@@ -113,7 +103,6 @@ def initialise_imprad(data: DataStructure):
         name_label=data.impurity_radiation.imp_label[4],
         z=7,
         m_species_amu=constants.M_NITROGEN_AMU,  # 14.00643, (14N,15N) Average mass
-        f_nd_species_electron=f_nd_species_electron,
         len_tab=N_IMPURITIY_LOSS_FUNCTION_POINTS,
         error=errorflag,
         data=data,
@@ -125,7 +114,6 @@ def initialise_imprad(data: DataStructure):
         name_label=data.impurity_radiation.imp_label[5],
         z=8,
         m_species_amu=constants.M_OXYGEN_AMU,  # 15.99903, (16O,17O,18O) Average mass
-        f_nd_species_electron=f_nd_species_electron,
         len_tab=N_IMPURITIY_LOSS_FUNCTION_POINTS,
         error=errorflag,
         data=data,
@@ -137,7 +125,6 @@ def initialise_imprad(data: DataStructure):
         name_label=data.impurity_radiation.imp_label[6],
         z=10,
         m_species_amu=constants.M_NEON_AMU,  # 20.1797 (20Ne,21Ne,22Ne) Average mass
-        f_nd_species_electron=f_nd_species_electron,
         len_tab=N_IMPURITIY_LOSS_FUNCTION_POINTS,
         error=errorflag,
         data=data,
@@ -149,7 +136,6 @@ def initialise_imprad(data: DataStructure):
         name_label=data.impurity_radiation.imp_label[7],
         z=14,
         m_species_amu=constants.M_SILICON_AMU,  # 28.084 (28Si,29Si,30Si) Average mass
-        f_nd_species_electron=f_nd_species_electron,
         len_tab=N_IMPURITIY_LOSS_FUNCTION_POINTS,
         error=errorflag,
         data=data,
@@ -161,7 +147,6 @@ def initialise_imprad(data: DataStructure):
         name_label=data.impurity_radiation.imp_label[8],
         z=18,
         m_species_amu=constants.M_ARGON_AMU,  # 39.948 (40Ar,36Ar,38Ar) Average mass
-        f_nd_species_electron=f_nd_species_electron,
         len_tab=N_IMPURITIY_LOSS_FUNCTION_POINTS,
         error=errorflag,
         data=data,
@@ -173,7 +158,6 @@ def initialise_imprad(data: DataStructure):
         name_label=data.impurity_radiation.imp_label[9],
         z=26,
         m_species_amu=constants.M_IRON_AMU,  # 55.845 (56Fe,54Fe,57Fe,58Fe) Average mass
-        f_nd_species_electron=f_nd_species_electron,
         len_tab=N_IMPURITIY_LOSS_FUNCTION_POINTS,
         error=errorflag,
         data=data,
@@ -186,7 +170,6 @@ def initialise_imprad(data: DataStructure):
         z=28,
         # 58.6934 (58Ni,60Ni,61Ni,62Ni,64Ni) Average mass
         m_species_amu=constants.M_NICKEL_AMU,
-        f_nd_species_electron=f_nd_species_electron,
         len_tab=N_IMPURITIY_LOSS_FUNCTION_POINTS,
         error=errorflag,
         data=data,
@@ -199,7 +182,6 @@ def initialise_imprad(data: DataStructure):
         z=36,
         # 83.798 (84Kr,86Kr,82Kr,80Kr,78Kr) Average mass
         m_species_amu=constants.M_KRYPTON_AMU,
-        f_nd_species_electron=f_nd_species_electron,
         len_tab=N_IMPURITIY_LOSS_FUNCTION_POINTS,
         error=errorflag,
         data=data,
@@ -212,7 +194,6 @@ def initialise_imprad(data: DataStructure):
         z=54,
         # 131.293 (132Xe,129Xe,131Xe,134Xe,136Xe) Average mass
         m_species_amu=constants.M_XENON_AMU,
-        f_nd_species_electron=f_nd_species_electron,
         len_tab=N_IMPURITIY_LOSS_FUNCTION_POINTS,
         error=errorflag,
         data=data,
@@ -225,7 +206,6 @@ def initialise_imprad(data: DataStructure):
         z=74,
         # 183.84 (184W,186W,182W,183W,180W) Average mass
         m_species_amu=constants.M_TUNGSTEN_AMU,
-        f_nd_species_electron=f_nd_species_electron,
         len_tab=N_IMPURITIY_LOSS_FUNCTION_POINTS,
         error=errorflag,
         data=data,
@@ -291,7 +271,6 @@ def init_imp_element(
     name_label: str,
     z: int,
     m_species_amu: float,
-    f_nd_species_electron: float,
     len_tab: int,
     error: int,
     data: DataStructure,
@@ -312,8 +291,6 @@ def init_imp_element(
         Species charge number
     m_species_amu : float
         Species atomic mass [amu]
-    f_nd_species_electron : float
-        Number density / electron density
     len_tab : int
         Length of temperature and Lz tables
     error : int
@@ -333,19 +310,15 @@ def init_imp_element(
     if error == 1:
         return
 
-    if n_species_index > len(data.impurity_radiation.impurity_arr_label):
+    if n_species_index > len(data.impurity_radiation.imp_label):
         raise ProcessValueError(
             "Illegal impurity number",
             number=n_species_index,
-            max=len(data.impurity_radiation.impurity_arr_label),
+            max=len(data.impurity_radiation.imp_label),
         )
 
-    data.impurity_radiation.impurity_arr_label[n_species_index - 1] = name_label
     data.impurity_radiation.impurity_arr_z[n_species_index - 1] = z
     data.impurity_radiation.m_impurity_amu_array[n_species_index - 1] = m_species_amu
-    data.impurity_radiation.f_nd_impurity_electron_array[n_species_index - 1] = (
-        f_nd_species_electron
-    )
     data.impurity_radiation.impurity_arr_len_tab[n_species_index - 1] = len_tab
 
     if len_tab > N_IMPURITIY_LOSS_FUNCTION_POINTS:
@@ -598,9 +571,9 @@ def calculate_impurity_radiation_power_density(
     )
 
     # W/m³ = nᵢ * nₑ * L(Z, Tₑ)
-    # nᵢ = f_nd_species_electron * nₑ
+    # nᵢ = fᵢ * nₑ
     return (
-        data.impurity_radiation.f_nd_impurity_electron_array[imp_element_index]
+        data.impurity_radiation.f_nd_impurity_electrons[imp_element_index]
         * nd_electron_profile
         * nd_electron_profile
         * power_loss_function
@@ -624,20 +597,13 @@ def element2index(element: str, data: DataStructure) -> int:
     Raises
     ------
     ProcessValueError
-        If the element is not found in impurity_arr_label
+        If the element is not found in imp_label
 
     """
     try:
-        return (
-            data.impurity_radiation.impurity_arr_label
-            .astype(str)
-            .tolist()
-            .index(element)
-        )
+        return data.impurity_radiation.imp_label.astype(str).tolist().index(element)
     except ValueError as e:
-        raise ProcessValueError(
-            f"Element {element} is not found in impurity_arr_label"
-        ) from e
+        raise ProcessValueError(f"Element {element} is not found in imp_label") from e
 
 
 class ImpurityRadiation:
@@ -659,7 +625,7 @@ def __init__(self, plasma_profile: PlasmaProfile, data_structure: DataStructure)
         self.data = data_structure
         self.plasma_profile = plasma_profile
         self.imp = np.nonzero(
-            self.data.impurity_radiation.f_nd_impurity_electron_array > 1.0e-30
+            self.data.impurity_radiation.f_nd_impurity_electrons > 1.0e-30
         )[0]
 
         self.pden_impurity_radiation_profile = np.zeros(
@@ -712,7 +678,7 @@ def calculate_species_radiation_powers(
         p_plasma_rad_impurities_mw = 0.0
         for index, label in enumerate(self.data.impurity_radiation.imp_label):
             pden_vol_avg_mw = 0.0
-            if self.data.impurity_radiation.f_nd_impurity_electron_array[index] > 1e-30:
+            if self.data.impurity_radiation.f_nd_impurity_electrons[index] > 1e-30:
                 pden_profile = calculate_impurity_radiation_power_density(
                     imp_element_index=index,
                     nd_electron_profile=self.plasma_profile.neprofile.profile_y,
diff --git a/process/models/physics/physics.py b/process/models/physics/physics.py
index 454a5824d1..3e2f6ce6cd 100644
--- a/process/models/physics/physics.py
+++ b/process/models/physics/physics.py
@@ -1134,7 +1134,7 @@ def run(self):
                     " is at least notable"
                 )
 
-            impurity_frac = self.data.impurity_radiation.f_nd_impurity_electron_array[
+            impurity_frac = self.data.impurity_radiation.f_nd_impurity_electrons[
                 self.data.reinke.impvardiv - 1
             ]
             po.write(
@@ -1263,7 +1263,7 @@ def plasma_composition(self):
                     np.array([self.data.physics.temp_plasma_electron_vol_avg_kev]),
                     self.data,
                 ).squeeze() * (
-                    self.data.impurity_radiation.f_nd_impurity_electron_array[imp]
+                    self.data.impurity_radiation.f_nd_impurity_electrons[imp]
                     * self.data.physics.nd_plasma_electrons_vol_avg
                 )
 
@@ -1300,7 +1300,7 @@ def plasma_composition(self):
 
         # Set hydrogen and helium relative impurity densities for
         # radiation calculations
-        self.data.impurity_radiation.f_nd_impurity_electron_array[
+        self.data.impurity_radiation.f_nd_impurity_electrons[
             impurity_radiation.element2index("H_", self.data)
         ] = (
             self.data.physics.nd_plasma_protons_vol_avg
@@ -1312,7 +1312,7 @@ def plasma_composition(self):
             + self.data.physics.nd_beam_ions
         ) / self.data.physics.nd_plasma_electrons_vol_avg
 
-        self.data.impurity_radiation.f_nd_impurity_electron_array[
+        self.data.impurity_radiation.f_nd_impurity_electrons[
             impurity_radiation.element2index("He", self.data)
         ] = (
             self.data.physics.f_plasma_fuel_helium3
@@ -1328,7 +1328,7 @@ def plasma_composition(self):
         for imp in range(N_IMPURITIES):
             if self.data.impurity_radiation.impurity_arr_z[imp] > 2:
                 self.data.physics.nd_plasma_impurities_vol_avg += (
-                    self.data.impurity_radiation.f_nd_impurity_electron_array[imp]
+                    self.data.impurity_radiation.f_nd_impurity_electrons[imp]
                     * self.data.physics.nd_plasma_electrons_vol_avg
                 )
 
@@ -1348,20 +1348,20 @@ def plasma_composition(self):
         # Set some relative impurity density variables
         # for the benefit of other routines
         self.data.physics.f_nd_plasma_carbon_electron = (
-            self.data.impurity_radiation.f_nd_impurity_electron_array[
+            self.data.impurity_radiation.f_nd_impurity_electrons[
                 impurity_radiation.element2index("C_", self.data)
             ]
         )
         self.data.physics.f_nd_plasma_oxygen_electron = (
-            self.data.impurity_radiation.f_nd_impurity_electron_array[
+            self.data.impurity_radiation.f_nd_impurity_electrons[
                 impurity_radiation.element2index("O_", self.data)
             ]
         )
         self.data.physics.f_nd_plasma_iron_argon_electron = (
-            self.data.impurity_radiation.f_nd_impurity_electron_array[
+            self.data.impurity_radiation.f_nd_impurity_electrons[
                 impurity_radiation.element2index("Fe", self.data)
             ]
-            + self.data.impurity_radiation.f_nd_impurity_electron_array[
+            + self.data.impurity_radiation.f_nd_impurity_electrons[
                 impurity_radiation.element2index("Ar", self.data)
             ]
         )
@@ -1374,7 +1374,7 @@ def plasma_composition(self):
         self.data.physics.n_charge_plasma_effective_vol_avg = 0.0
         for imp in range(N_IMPURITIES):
             self.data.physics.n_charge_plasma_effective_vol_avg += (
-                self.data.impurity_radiation.f_nd_impurity_electron_array[imp]
+                self.data.impurity_radiation.f_nd_impurity_electrons[imp]
                 * impurity_radiation.calculate_average_charge_at_temp(
                     imp,
                     np.array([self.data.physics.temp_plasma_electron_vol_avg_kev]),
@@ -1444,7 +1444,7 @@ def plasma_composition(self):
             if self.data.impurity_radiation.impurity_arr_z[imp] > 2:
                 self.data.physics.m_ions_total_amu += (
                     self.data.physics.nd_plasma_electrons_vol_avg
-                    * self.data.impurity_radiation.f_nd_impurity_electron_array[imp]
+                    * self.data.impurity_radiation.f_nd_impurity_electrons[imp]
                     * self.data.impurity_radiation.m_impurity_amu_array[imp]
                 )
 
@@ -1493,7 +1493,7 @@ def plasma_composition(self):
         for imp in range(N_IMPURITIES):
             if self.data.impurity_radiation.impurity_arr_z[imp] > 2:
                 self.data.physics.n_charge_plasma_effective_mass_weighted_vol_avg += (
-                    self.data.impurity_radiation.f_nd_impurity_electron_array[imp]
+                    self.data.impurity_radiation.f_nd_impurity_electrons[imp]
                     * impurity_radiation.calculate_average_charge_at_temp(
                         imp,
                         np.array([self.data.physics.temp_plasma_electron_vol_avg_kev]),
@@ -1760,7 +1760,7 @@ def calculate_effective_charge_ionisation_profiles(self):
             zeff_profile[i] = 0.0
             for imp in range(N_IMPURITIES):
                 zeff_profile[i] += (
-                    self.data.impurity_radiation.f_nd_impurity_electron_array[imp]
+                    self.data.impurity_radiation.f_nd_impurity_electrons[imp]
                     * impurity_radiation.calculate_average_charge_at_temp(
                         imp,
                         np.array([self.plasma_profile.teprofile.profile_y[i]]),
@@ -3154,16 +3154,8 @@ def output_temperature_density_profile_info(self) -> None:
         po.oblnkl(self.outfile)
 
         for imp in range(N_IMPURITIES):
-            # MDK Update f_nd_impurity_electrons, as this will make the ITV output
-            # work correctly.
-            self.data.impurity_radiation.f_nd_impurity_electrons[imp] = (
-                self.data.impurity_radiation.f_nd_impurity_electron_array[imp]
-            )
             str1 = (
-                self.data.impurity_radiation
-                .impurity_arr_label[imp]
-                .item()
-                .replace("_", "")
+                self.data.impurity_radiation.imp_label[imp].item().replace("_", "")
                 + " concentration"
             )
             str2 = f"(f_nd_impurity_electrons({imp + 1:02}))"
diff --git a/tests/unit/models/physics/test_physics.py b/tests/unit/models/physics/test_physics.py
index ecb59f8792..30e4a0cf29 100644
--- a/tests/unit/models/physics/test_physics.py
+++ b/tests/unit/models/physics/test_physics.py
@@ -1233,7 +1233,7 @@ def test_conhas(physics):
 class PlasmaCompositionParam(NamedTuple):
     f_beam_tritium: Any = None
 
-    f_nd_impurity_electron_array: Any = None
+    f_nd_impurity_electrons: Any = None
 
     impurity_arr_z: Any = None
 
@@ -1337,7 +1337,7 @@ class PlasmaCompositionParam(NamedTuple):
     [
         PlasmaCompositionParam(
             f_beam_tritium=9.9999999999999995e-07,
-            f_nd_impurity_electron_array=np.array([
+            f_nd_impurity_electrons=np.array([
                 0.90000000000000002,
                 0.10000000000000001,
                 0,
@@ -1449,7 +1449,7 @@ class PlasmaCompositionParam(NamedTuple):
         ),
         PlasmaCompositionParam(
             f_beam_tritium=9.9999999999999995e-07,
-            f_nd_impurity_electron_array=np.array([
+            f_nd_impurity_electrons=np.array([
                 0.78128535,
                 0.10000000000000001,
                 0,
@@ -1576,7 +1576,7 @@ def test_plasma_composition(plasmacompositionparam, monkeypatch, physics):
         plasmacompositionparam.f_beam_tritium,
     )
     for field in [
-        "f_nd_impurity_electron_array",
+        "f_nd_impurity_electrons",
         "impurity_arr_z",
         "m_impurity_amu_array",
     ]:
@@ -1625,7 +1625,7 @@ def test_plasma_composition(plasmacompositionparam, monkeypatch, physics):
 
     physics.plasma_composition()
 
-    assert physics.data.impurity_radiation.f_nd_impurity_electron_array == pytest.approx(
+    assert physics.data.impurity_radiation.f_nd_impurity_electrons == pytest.approx(
         plasmacompositionparam.expected_impurity_arr_frac
     )