A dimensionless number, defined by the identity
are the characteristic values
of the magnetic induction and the velocity of
the fluid; l0
is the characteristic dimension; σ
and ρ are the specific electrical conductivity
and the density of the fluid.
Comment on terms 148-151. The dimen·
sional variables appearing in the dimensionless
numbers Ha, ReM
, and S are given in the
SI system of units.