Ambipolar Drift Heating in Turbulent Molecular Clouds

Abstract

Although thermal pressure is unimportant dynamically in most molecular gas, the temperature is an important diagnostic of dynamical processes and physical conditions. This is the first of two papers on thermal equilibrium in molecular clouds. We present calculations of frictional heating by ion-neutral (or ambipolar) drift in three-dimensional simulations of turbulent, magnetized molecular clouds. We show that ambipolar drift heating is a strong function of position in a turbulent cloud, and its average value can be significantly larger than the average cosmic ray heating rate. The volume averaged heating rate per unit volume due to ambipolar drift, H_AD ~ |JxB|^2 ~ B^4/L_B^2, is found to depend on the rms Alfvenic Mach number, M_A, and on the average field strength, as H_AD ~ M_A^2<|B|>^4. This implies that the typical scale of variation of the magnetic field, L_B, is inversely proportional to M_A, which we also demonstrate.

37 pages, 9 figures included

References in corpus (5)

• Dissipation in Compressible MHD Turbulence
• The Energy Dissipation Rate of Supersonic, Magnetohydrodynamic Turbulence in Molecular Clouds
• A Super-Alfvenic Model of Dark Clouds
• Nonlinear Evolution of the Magnetorotational Instability in Ion-Neutral Disks
• Synthetic Molecular Clouds from Supersonic MHD and Non-LTE Radiative Transfer Calculations

Cited by in corpus (36)

• Interstellar Turbulence I: Observations and Processes
• The Stellar IMF from Turbulent Fragmentation
• Interstellar Turbulence II: Implications and Effects
• The Turbulent Shock Origin of Proto--Stellar Cores
• The Formation of Stellar Clusters: Mass Spectra from Turbulent Molecular Cloud Fragmentation
• Theoretical Models of Polarized Dust Emission from Protostellar Cores
• Kolmogorov-Burgers Model for Star Forming Turbulence
• Comparing Numerical Methods for Isothermal Magnetized Supersonic Turbulence
• Physical Processes in Star Formation
• Sub-Alfvenic Non-Ideal MHD Turbulence Simulations with Ambipolar Diffusion: I. Turbulence Statistics
• The Inability of Ambipolar Diffusion to set a Characteristic Mass Scale in Molecular Clouds
• Chondrule Formation and Protoplanetary Disk Heating by Current Sheets in Non-Ideal Magnetohydrodynamic Turbulence
• Diffusion in supersonic, turbulent, compressible flows
• Simulating hydromagnetic processes in star formation: introducing ambipolar diffusion into an adaptive mesh refinement code
• An Explicit Scheme for Incorporating Ambipolar Diffusion in a Magnetohydrodynamics Code
• Molecular Tracers of Turbulent Shocks in Giant Molecular Clouds
• Can WNM survive inside Molecular Clouds ?
• DISPATCH: A Numerical Simulation Framework for the Exa-scale Era. I. Fundamentals
• Ambipolar diffusion in the Bifrost code
• Ambipolar Diffusion Heating in Turbulent Systems
• Turbulent energy dissipation and intermittency in ambipolar diffusion magnetohydrodynamics
• Magnetic Field Orientation in Self-Gravitating Turbulent Molecular Clouds
• Chaotic cold accretion in giant elliptical galaxies heated by AGN cosmic rays
• Cooling Rates of Molecular Clouds Based on Numerical MHD Turbulence and non-LTE Radiative Transfer
• The effect of ambipolar resistivity on the formation of dense cores
• Energy Cascades in Astrophysical Plasma
• Formation of low-mass condensations in the molecular cloud cores via thermal instability
• Ambipolar diffusion in large Prandtl number turbulence
• Modulation of waves due to charge-exchange collisions in magnetized partially ionized space plasma
• Ambipolar Diffusion-Mediated Thermal Fronts in the Neutral ISM
• GMC Collisions As Triggers of Star Formation. IV. The Role of Ambipolar Diffusion
• The Astrochemical Evolution of Turbulent Giant Molecular Clouds : I - Physical Processes and Method of Solution for Hydrodynamic, Embedded Starless Clouds
• Ambipolar diffusion: Self-similar solutions and MHD code testing. Cylindrical symmetry
• Linear modes in the partially ionized heliosphere plasma
• Dynamics of Alfvén waves in partially ionized astrophysical plasmas
• Global Signals of the First Molecules from the Dark Ages in the Presence of Primordial Magnetic Fields