http://arxiv.org/abs/2204.07681
Supernova ejecta and stellar winds are believed to produce interstellar dust grains with relatively large sizes. One way to produce smaller grains is via the shattering of large grains that have been stochastically accelerated to high velocities. To understand this stochastic acceleration, we have implemented novel magnetohydrodynamic(MHD)-particle-in-cell(PIC) methods into the astrophysical fluid code RAMSES. We treat dust grains as a set of massive “superparticles” that experience aerodynamic drag and Lorentz force. We subject our code to a range of numerical tests designed to validate our method in different physical conditions, as well as to illustrate possible mechanisms by which grains can be accelerated. As a final test as well as a foundation for future work, we present the results of decaying dusty MHD turbulence simulations with grain parameters chosen to resemble 1-2 $\mu$m grains in typical cold neutral medium conditions. We find that in these conditions, these grains can be effectively accelerated to well beyond their shattering velocities. This is true for both electrically charged and neutral grains. While the peak of the gas-grain relative drift velocity distribution is higher for neutral grains, the drift velocity distribution of charged grains exhibits an extended exponential tail out to much greater velocities. Even so, the shapes of the distributions are such that the extra gas-grain coupling provided by the Lorentz force offers grains relative protection from shattering.
E. Moseley, R. Teyssier and B. Draine
Tue, 19 Apr 22
20/52
Comments: 21 pages, 12 figures, submitted to MNRAS
You must be logged in to post a comment.