  Single hadron azimuthal asymmetries of positive and negative hadrons produced
in muon semi-inclusive deep inelastic scattering off longitudinally polarised
deuterons are determined using the 2006 COMPASS data and also combined all
deuteron COMPASS data. For each hadron charge, the dependence of the azimuthal
asymmetry on the hadron azimuthal angle $\phi$ is obtained by means of a
five-parameter fitting function that besides a $\phi$-independent term includes
four modulations predicted by theory: $\sin\phi$, $\sin 2 \phi$, $\sin 3\phi$
and $\cos\phi$. The amplitudes of the five terms have been extracted, first,
for the hadrons in the whole available kinematic region. In further fits,
performed for hadrons from a restricted kinematic region, the $\phi$-dependence
is determined as a function of one of three variables (Bjorken-$x$, fractional
energy of virtual photon taken by the outgoing hadron and hadron transverse
momentum), while disregarding the others. Except the $\phi$-independent term,
all the modulation amplitudes are very small, and no clear kinematic dependence
could be observed within experimental uncertainties.
