ATLASRECTS-6655 : Returning huge value for the mag field from the getFieldZR when no B is present creates issues.
ATLASRECTS-6655 Returning a huge value (1.997 kT) for the mag field from the getFieldZR method when no B is present creates issues.
Return the defaultB (small value = 1e-8 kT = 0.1 Gauss) in the cases where a magnetic field is not present