Switch psi sources to being <j.B>

Author: theo-brown

torax/_src/sources/source_profiles.py

@@ -121,10 +121,12 @@ def merge(
     )
 
   def total_psi_sources(self, geo: geometry.Geometry) -> jax.Array:
+    # All psi sources are assumed to be parallel to the magnetic field, ie
+    # self.psi.values() is <j.B>
     total = self.bootstrap_current.j_bootstrap
     total += sum(self.psi.values())
     mu0 = constants.CONSTANTS.mu0
-    prefactor = 8 * geo.vpr * jnp.pi**2 * geo.B_0 * mu0 * geo.Phi_b / geo.F**2
+    prefactor = 8 * geo.vpr * jnp.pi**2 * mu0 * geo.Phi_b / geo.F**2
     return -total * prefactor
 
   def total_sources(