update bt to b_plasma_toroidal_on_axis so scan notebook plots work

Author: clmould

examples/scan.ipynb

@@ -86,7 +86,7 @@
     "        \"-f\",\n",
     "        str(mfile_name),\n",
     "        \"-yv\",\n",
-    "        \"bt rmajor p_plant_electric_net_mw p_fusion_total_mw capcost\",\n",
+    "        \"b_plasma_toroidal_on_axis rmajor p_plant_electric_net_mw p_fusion_total_mw capcost\",\n",
     "        \"--outputdir\",\n",
     "        str(output_dir),\n",
     "    ]\n",
@@ -97,7 +97,7 @@
  "metadata": {
   "celltoolbar": "Slideshow",
   "kernelspec": {
-   "display_name": ".venv",
+   "display_name": "env",
    "language": "python",
    "name": "python3"
   },