expose BIL-2000 option

There is an artifact in IRI when used with the standard bottomside model. Dieter Bilitza suggested using the JF(4) switch (note: that's jf(3) in Python indexing) to use the BIL-2000 model which doesn't have the bug. This update exposes this switch to the user.

src/pyglow/iri.py

@@ -60,7 +60,8 @@ def run(
         compute_Ni=True,
         f107=None,
         f107a=None,
-	f1_layer=True,
+        f1_layer=True,
+        bil2000=False,
     ):
         """
         Run IRI model at point time/location and update the object state
@@ -82,7 +83,8 @@ def run(
         :param compute_Ni: Switch to compute Ni
         :param f107: User specified F107
         :param f107a: User specified F107A
-	:param f1_layer: If True (default) include F1-layer (JF switches 19,20 = True)
+        :param f1_layer: If True (default) include F1-layer (JF switches 19,20 = True)
+        :param bil2000: If True, use Bil-2000 model for bottomside (JF switch 4). Default IRI is False
         """
 
         if version == 2016:
@@ -163,6 +165,10 @@ def init_iri(): return False
             # Set jf(19) and jf(20) to False (in Fortran index)
             jf[18] = 0
             jf[19] = 0
+
+        if bil2000:
+            # Set jf(4) to True (in Fortran index)
+            jf[3] = True
 
         # Get current directory:
         my_pwd = os.getcwd()

src/pyglow/pyglow.py

@@ -165,6 +165,7 @@ def run_iri(
         compute_Te_Ti=True,
         compute_Ni=True,
         f1_layer=True,
+        bil2000=False,
     ):
         """
         Executes IRI and assigns results to instance.
@@ -175,7 +176,8 @@ def run_iri(
         :param compute_Ne: Switch to compute Ne
         :param compute_Te_Ti: Switch to compute Te and Ti
         :param compute_Ni: Switch to compute Ni
-	:param f1_layer: If True (default) include F1-layer (JF switches 19,20 = True)
+        :param f1_layer: If True (default) include F1-layer (JF switches 19,20 = True)
+        :param bil2000: If True, use Bil-2000 model for bottomside (JF switch 4). Default IRI is False
         """
 
         # Check if user supplies indices:
@@ -202,6 +204,7 @@ def run_iri(
             f107=f107,
             f107a=f107a,
             f1_layer=f1_layer,
+            bil2000=bil2000,
         )
 
         # Assign output of IRI: