Other
Scientific paper
Oct 1986
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1986inpr.conf...71f&link_type=abstract
In NASA. Ames Research Center Summer School on Interstellar Processes: Abstracts of Contributed Papers p 71-72 (SEE N87-15043 0
Other
1
Interstellar Gas, Molecular Clouds, Shock Wave Propagation, Endothermic Reactions, Gas Ionization, Magnetic Fields
Scientific paper
Considerable effort in recent years has been devoted to the study of shocks in the diffuse interstellar medium. This work has been motivated partly by the observations of rotationally excited states of H2, and partly by the realization that species such as CH(+), OH and H2O might be formed preferentially in hot, post-shock gas. The problem of CH(+) and the difficulties encountered when trying to explain the high column densities, observed along lines of sight to certain hot stars, have been reviewed earlier. The importance of a transverse magnetic field on the structure of an interstellar shock was also demonstrated earlier. Transverse magnetic fields above a critical strength give rise to an acceleration zone or precursor, in which the parameters on the flow vary continuously. Chemical reactions, which change the degree of ionization of the gas, also modify the structure of the shock considerably. Recent work has shown that large column densities of CH(+) can be produced in magnetohydrodynamic shock models. Shock speeds Us approx. = 10 km/s and initial magnetic field strengths of a few micro G are sufficient to produce ion-neutral drift velocities which can drive the endothermic C(+)(H2,H)CH(+) reaction. It was also shown that single-fluid hydrodynamic models do not generate sufficiently large column densities of CH(+) unless unacceptably high shock velocities (us approx. 20 km/s) are assumed in the models. Thus, the observed column densities of CH(+) provide a constraint on the mode of shock propagation in diffuse clouds. More precisely, they determine a lower limit to the ion-neutral drift velocity.
Flower David R.
Hartquist Thomas W.
Pineau-des-Forets G.
Roueff Evelyne
No associations
LandOfFree
Observational discrimination between modes of shock propagation in interstellar clouds: Predictions of CH+ and SH+ column densities in diffuse clouds does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Observational discrimination between modes of shock propagation in interstellar clouds: Predictions of CH+ and SH+ column densities in diffuse clouds, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Observational discrimination between modes of shock propagation in interstellar clouds: Predictions of CH+ and SH+ column densities in diffuse clouds will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1737935