Magnetic flux loss from interstellar clouds with various grain-size distributions
R. Nishi, T. Nakano, T. Umebayashi;
ApJ, 1991, 368, 181
ABSTRACT:The densities of charged particles and the dissipation of magnetic fields in interstellar clouds shielded from UV radiation and having
densities between 1000 and 10 to the 13th/cu cm are investigated.
The effect of
the electric polarization of the gains on collision with ions and
electrons is taken into account, and different models for the grain size
distribution are used.
It is found that the metal ions are not the major
constitutents among the charged particles due to their ability to recombine
efficiently on grain surfaces.
In a cloud where the magnetic field strength is
nearly equal to the critical field with which the magnetic force balances
self-gravity, the magnetic flux loss time is shorter than the free-fall time only if
the density is greater than the critical density, which is given for the
different models.
In all cases the magnetic field is strongly coupled to the gas
and the magnetic flux of the cloud cannot decrease far below the critical
flux.
KEYWORDS: charged particles, cosmic dust, grain size, interstellar magnetic fields, interstellar matter, magnetic flux, abundance, astronomical models, molecular clouds, particle density (concentration), particle size distribution, star formation
PERSOKEY:magnetic field, dust, size distribution, ,
CODE: nishi91