The phenomenology of magnetohydrodynamic (MHD) turbulence proposed by R. H.
Kraichnan, and its consequences for energy spectra and energy decay laws i
n the high Reynolds number self-similar regime, are first reviewed. After r
ecalling the exact relationships for MHD derived in the spirit of the so-ca
lled "4/5" law of Kolmogorov, such laws are used to compute intermittency e
xponents for statistically steady MHD flows in two space dimensions. These
exponents are evaluated both for the structure functions of order p built o
n the physical variables-velocity v and magnetic field b, or their combinat
ion, through the Elsasser variables z(+/-) = v +/- b-and for the flux varia
bles Y-p(+/-)(r) = [[delta z(L)(-/+)(r)(delta z(i)(+/-)(r))(2)](p/3)], wher
e L denotes the longitudinal components of the fields. There are indication
s that these nonlinear fluxes scale in a manner similar to that of noncondu
cting fluids, whereas the physical v, b, z(+/-) fields are more intermitten
t than in the neutral fluid case. (C) 1999 American Institute of Physics. [
S1070-6631(99)01608-6].