diff --git a/plasmapy/physics/transport.py b/plasmapy/physics/transport.py
index 75073cbd..8af344d3 100644
--- a/plasmapy/physics/transport.py
+++ b/plasmapy/physics/transport.py
@@ -8,21 +8,22 @@
 from .parameters import Debye_length
 
 
-@check_quantity({"n_e": {"units": units.m**-3},
-                 "T": {"units": units.K, "can_be_negative": False}
+@check_quantity({"T": {"units": units.K, "can_be_negative": False},
+                 "n_e": {"units": units.m**-3}
                  })
-def Coulomb_logarithm(n_e, T, particles, V=None):
+def Coulomb_logarithm(T, n_e, particles, V=None):
     r"""Estimates the Coulomb logarithm.
 
     Parameters
     ----------
-    n_e : Quantity
-        The electron density in units convertible to per cubic meter.
 
     T : Quantity
-        Temperature in units of temperature or energy per particle,
-        which is assumed to be equal for both the test particle and
-        the target particle
+    Temperature in units of temperature or energy per particle,
+    which is assumed to be equal for both the test particle and
+    the target particle
+
+    n_e : Quantity
+        The electron density in units convertible to per cubic meter.
 
     particles : tuple
         A tuple containing string representations of the test particle
@@ -90,9 +91,9 @@ def Coulomb_logarithm(n_e, T, particles, V=None):
     Examples
     --------
     >>> from astropy import units as u
-    >>> Coulomb_logarithm(T=1e6*units.K, n_e=1e19*units.m**-3, ('e', 'p'))
+    >>> Coulomb_logarithm(T=1e6*u.K, n_e=1e19*u.m**-3, ('e', 'p'))
     14.748259780491056
-    >>> Coulomb_logarithm(1e6*units.K, 1e19*units.m**-3, ('e', 'p'),
+    >>> Coulomb_logarithm(1e6*u.K, 1e19*u.m**-3, ('e', 'p'),
                           V=1e6*u.m/u.s)
 
     References

Check consistency of argument ordering in physics
Here are a few example signatures straight from `physics.transport`:

```
def Coulomb_logarithm(n_e, T, particles, V=None):
def Debye_length(T_e, n_e):
def Debye_number(T_e, n_e):
def upper_hybrid_frequency(B, n_e):
```
It would be nice to ensure that non-keyword arguments, where applicable, have the same ordering - like in other scientific packages, like Numpy, a consistent API is helpful for being able to call multiple functions without having to check the signature each time you call them.

Any consistent ordering would be welcome - but common sense takes precedence.
diff --git a/plasmapy/physics/tests/test_transport.py b/plasmapy/physics/tests/test_transport.py
index 3e5333a0..a1553e55 100644
--- a/plasmapy/physics/tests/test_transport.py
+++ b/plasmapy/physics/tests/test_transport.py
@@ -18,37 +18,37 @@ def test_Coulomb_logarithm():
     particles = ('e', 'p')
 
     for i in range(3):
-        assert np.isclose(Coulomb_logarithm(n_e[i], T[i], particles),
+        assert np.isclose(Coulomb_logarithm(T[i], n_e[i], particles),
                           Lambda[i], atol=0.01)
 
-    assert np.isclose(Coulomb_logarithm(5*u.m**-3, 1*u.eV, ('e', 'e')),
-                      Coulomb_logarithm(5*u.m**-3, 11604.5220*u.K, ('e', 'e')))
+    assert np.isclose(Coulomb_logarithm(1*u.eV, 5*u.m**-3, ('e', 'e')),
+                      Coulomb_logarithm(11604.5220*u.K, 5*u.m**-3, ('e', 'e')))
 
-    assert np.isclose(Coulomb_logarithm(1e9*u.cm**-3, 1e2*u.K, ('e', 'p')),
+    assert np.isclose(Coulomb_logarithm(1e2*u.K, 1e9*u.cm**-3, ('e', 'p')),
                       5.97, atol=0.01)
 
-    assert np.isclose(Coulomb_logarithm(1e9*u.cm**-3, 1e7*u.K, ('e', 'p')),
+    assert np.isclose(Coulomb_logarithm(1e7*u.K, 1e9*u.cm**-3, ('e', 'p')),
                       21.6, atol=0.1)
 
-    assert np.isclose(Coulomb_logarithm(1e24*u.cm**-3, 1e8*u.K, ('e', 'p')),
+    assert np.isclose(Coulomb_logarithm(1e8*u.K, 1e24*u.cm**-3, ('e', 'p')),
                       6.69, atol=0.01)
 
-    assert np.allclose(Coulomb_logarithm(n_e, T, particles), Lambda, atol=0.01)
+    assert np.allclose(Coulomb_logarithm(T, n_e, particles), Lambda, atol=0.01)
 
-    assert np.isclose(Coulomb_logarithm(5*u.m**-3, 1e5*u.K, ('e', 'e'),
+    assert np.isclose(Coulomb_logarithm(1e5*u.K, 5*u.m**-3, ('e', 'e'),
                                         V=1e4*u.m/u.s), 21.379082011)
 
     with pytest.raises(UserWarning):
-        Coulomb_logarithm(1*u.m**-3, 1e5*u.K, ('e', 'p'), 299792458*u.m/u.s)
+        Coulomb_logarithm(1e5*u.K, 1*u.m**-3, ('e', 'p'), 299792458*u.m/u.s)
 
     with pytest.raises(u.UnitConversionError):
-        Coulomb_logarithm(1*u.m**-3, 1e5*u.g, ('e', 'p'), 29979245*u.m/u.s)
+        Coulomb_logarithm(1e5*u.g, 1*u.m**-3, ('e', 'p'), 29979245*u.m/u.s)
 
     with pytest.raises(ValueError):
-        Coulomb_logarithm(5*u.m**-3, 1*u.K, ('e'))
+        Coulomb_logarithm(1*u.K, 5*u.m**-3, ('e'))
 
     with pytest.raises(ValueError):
-        Coulomb_logarithm(5*u.m**-3, 1*u.K, ('e', 'g'))
+        Coulomb_logarithm(1*u.K, 5*u.m**-3, ('e', 'g'))
 
     with pytest.raises(ValueError):
-        Coulomb_logarithm(5*u.m**-3, 1*u.K, ('e', 'D'))
+        Coulomb_logarithm(1*u.K, 5*u.m**-3, ('e', 'D'))

pip install -e .[dev]
parse_log_pytest
requirements.txt
pytest
apt-get update apt-get install -y gcc
3.9
requirements/base.txt
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
astropy==6.0.1
astropy-iers-data==0.2025.3.31.0.36.18
exceptiongroup==1.2.2
iniconfig==2.1.0
numpy==1.26.4
packaging==24.2
-e git+https://github.com/PlasmaPy/PlasmaPy.git@47925baeaac18c58c758b4ab50fabb44087cd800#egg=plasmapy
pluggy==1.5.0
pyerfa==2.0.1.5
pytest==8.3.5
PyYAML==6.0.2
scipy==1.13.1
tomli==2.2.1

name: PlasmaPy
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - ca-certificates=2025.2.25=h06a4308_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.4.4=h6a678d5_1
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - ncurses=6.4=h6a678d5_0
  - openssl=3.0.16=h5eee18b_0
  - pip=25.0=py39h06a4308_0
  - python=3.9.21=he870216_1
  - readline=8.2=h5eee18b_0
  - setuptools=75.8.0=py39h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - tzdata=2025a=h04d1e81_0
  - wheel=0.45.1=py39h06a4308_0
  - xz=5.6.4=h5eee18b_1
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - astropy==6.0.1
      - astropy-iers-data==0.2025.3.31.0.36.18
      - exceptiongroup==1.2.2
      - iniconfig==2.1.0
      - numpy==1.26.4
      - packaging==24.2
      - pluggy==1.5.0
      - pyerfa==2.0.1.5
      - pytest==8.3.5
      - pyyaml==6.0.2
      - scipy==1.13.1
      - tomli==2.2.1
prefix: /opt/conda/envs/PlasmaPy

plasmapy/physics/tests/test_transport.py::test_Coulomb_logarithm
plasmapy/physics/transport.py
plasmapy/physics/transport.py