Statistical Studies of Magnetohydrodynamic Turbulence in Two Phase Simulations
Rivera, Emy M. ( University of Puerto Rico at Mayaguez, Puerto Rico ); Burkhart, B. K. ( University of Wisconsin - Madison ); Lazarian, A. ( University of Wisconsin - Madison ) show affiliations
American Astronomical Society, AAS Meeting #221, #349.02
Published in Jan 2013
HI gas in the interstellar medium exists in two of the classical ISM phase: the 'cold phase' and 'warm phase'. In general, these phases are in thermal and pressure equilibrium with each other, however some fraction of the gas is thermally unstable. Regardless of the temperature, turbulence is expected to exist in HI gas throughout the ISM and numerous statistical measures for gauging turbulence have been applied in the past to HI 21 cm data despite the fact that often these statistics are often tested using isothermal simulations. We applied PDFs and statistical moments to two phase simulations. The statistical moments and PDFs were compared with the ones obtained from isothermal gas. We found that the warm phase component was mainly subsonic while the cold component was mainly supersonic. The natural logarithm of density PDFs for the warm component was not gaussian shaped as for isothermal gas, but seemed to be composed of two gaussians. One of the gaussians was corresponding to a component of the warm gas being dominated by thermal pressure while another being dominated more by turbulence. The moments for both components of the two phase were similar to the moments for isothermal simulations. This work was partially supported by the National Science Foundation's REU program through NSF Award AST-1004881
(c) 2013: American Astronomical Society