%0 Generic %1 gent2012supernovaregulated %A Gent, F. A. %A Shukurov, A. %A Fletcher, A. %A Sarson, G. R. %A Mantere, M. J. %D 2012 %K ism multi-phase turbulence %T The supernova-regulated ISM. I. The multi-phase structure %U http://arxiv.org/abs/1204.3567 %X We simulate the multiphase ISM randomly heated and stirred by supernovae, with gravity, differential rotation and other parameters of the solar neighbourhood. Here we describe in detail both numerical and physical aspects of the model, including injection of thermal and kinetic energy by SN explosions, radiative cooling, photoelectric heating and various transport processes. With a three dimensional domain extending 1x1kpc^2 horizontally and 2kpc vertically, the model routinely spans gas number densities 10^-5-10^2cm^-3, temperatures 10-10^8K, local velocities up to 10^3kms^-1 (with Mach numbers to 25). The working numerical resolution of 4pc has been selected via simulations of a single expanding SN remnant, where we closely reproduce, at this resolution, analytical solutions for the adiabatic and snowplough regimes. The thermal structure of the modelled ISM is classified using the altitude variation of the fractional volumes occupied by gas in relatively narrow temperature bands. We confirm that most of the complexity can be captured in terms of just three phases, separated by temperature borderlines at about 10^3K and 5x10^5K. The distribution of gas densities within each phase is approximately lognormal. We clarify the connection between the fractional volume of a phase and its various proxies, and derive an exact relation between the fractional volume and the filling factors defined in terms of the volume and probabilistic averages. These results are discussed in both observational and computational contexts. The correlation scale of the random flows is calculated from the velocity autocorrelation function; it is of order 100pc and tends to grow with distance from the midplane. We use two distinct parameterizations of radiative cooling to show that the multiphase structure of the gas is robust, as it does not depend significantly on this choice.

@misc{gent2012supernovaregulated, abstract = {We simulate the multiphase ISM randomly heated and stirred by supernovae, with gravity, differential rotation and other parameters of the solar neighbourhood. Here we describe in detail both numerical and physical aspects of the model, including injection of thermal and kinetic energy by SN explosions, radiative cooling, photoelectric heating and various transport processes. With a three dimensional domain extending 1x1kpc^2 horizontally and 2kpc vertically, the model routinely spans gas number densities 10^-5-10^2cm^-3, temperatures 10-10^8K, local velocities up to 10^3kms^-1 (with Mach numbers to 25). The working numerical resolution of 4pc has been selected via simulations of a single expanding SN remnant, where we closely reproduce, at this resolution, analytical solutions for the adiabatic and snowplough regimes. The thermal structure of the modelled ISM is classified using the altitude variation of the fractional volumes occupied by gas in relatively narrow temperature bands. We confirm that most of the complexity can be captured in terms of just three phases, separated by temperature borderlines at about 10^3K and 5x10^5K. The distribution of gas densities within each phase is approximately lognormal. We clarify the connection between the fractional volume of a phase and its various proxies, and derive an exact relation between the fractional volume and the filling factors defined in terms of the volume and probabilistic averages. These results are discussed in both observational and computational contexts. The correlation scale of the random flows is calculated from the velocity autocorrelation function; it is of order 100pc and tends to grow with distance from the midplane. We use two distinct parameterizations of radiative cooling to show that the multiphase structure of the gas is robust, as it does not depend significantly on this choice.}, added-at = {2012-04-17T17:40:15.000+0200}, author = {Gent, F. A. and Shukurov, A. and Fletcher, A. and Sarson, G. R. and Mantere, M. J.}, biburl = {https://www.bibsonomy.org/bibtex/22c810f7544f4572d709ab7b615f2195c/miki}, description = {[1204.3567] The supernova-regulated ISM. I. The multi-phase structure}, interhash = {cee6fbe5220e5c3a445b5abf3f258313}, intrahash = {2c810f7544f4572d709ab7b615f2195c}, keywords = {ism multi-phase turbulence}, note = {cite arxiv:1204.3567}, timestamp = {2012-04-17T17:40:15.000+0200}, title = {The supernova-regulated ISM. I. The multi-phase structure}, url = {http://arxiv.org/abs/1204.3567}, year = 2012 }