def mean_parallel_B(rm=0.0, dm=100.0):
	"""
	Accepts a rotation measure (in rad/m^2) and dispersion measure (in pc/cm^3) and 
	returns the approximate mean value for the paralelle magnetic field compoent along 
	the line of sight, in Gauss.

	Conversion to Tesla is: 1 T = 10^4 G
	"""

	b_los = 1.23 * (rm / dm)

	return b_los / 1.0e6