Non-ideal magnetohydrodynamic simulations of the first star formation: the effect of ambipolar diffusion

Abstract

In the present-day universe, magnetic fields play such essential roles in star formation as angular momentum transport and outflow driving, which control circumstellar disc formation/fragmentation and also the star formation efficiency. While only a much weaker field has been believed to exist in the early universe, recent theoretical studies find that strong fields can be generated by turbulent dynamo during the gravitational collapse. Here, we investigate the gravitational collapse of a cloud core ($\sim 10^3\mathrm{c}{\mathrm{m}}^{-3}$) up to protostar formation ($\sim 10^{20}\mathrm{c}{\mathrm{m}}^{-3}$) by non-ideal magnetohydrodynamics (MHD) simulations considering ambipolar diffusion (AD), the dominant non-ideal effects in the primordial-gas. We systematically study rotating cloud cores either with or without turbulence and permeated with uniform fields of different strengths. We find that AD can slightly suppress the field growth by dynamo especially on scales smaller than the Jeans-scale at the density range $10^{10}-10^{14}\mathrm{c}{\mathrm{m}}^{-3}$, while we could not see the AD effect on the temperature evolution, since the AD heating rate is always smaller than compression heating. The inefficiency of AD makes the field as strong as $10^3-10^5\mathrm{G}$ near the formed protostar, much stronger than in the present-day cases, even in cases with initially weak fields. The magnetic field affects the inflow motion when amplified to the equipartition level with turbulence on the Jeans-scale, although disturbed fields do not launch winds. This might suggest that dynamo amplified fields have smaller impact on the dynamics in the later accretion phase than other processes such as ionisation feedback.

15 pages, 11 figures, 2 tables. Accepted for publication in MNRAS

References in corpus (40)

• Protostar Formation in the Early Universe
• Simulations of nonhelical hydromagnetic turbulence
• Primordial Star Formation under the Influence of Far Ultraviolet Radiation: 1540 Cosmological Halos and the Stellar Mass Distribution
• A new Jeans resolution criterion for (M)HD simulations of self-gravitating gas: Application to magnetic field amplification by gravity-driven turbulence
• The Formation of the First Stars II. Radiative Feedback Processes and Implications for the Initial Mass Function
• Magnetic Fields in Dark Cloud Cores: Arecibo OH Zeeman Observations
• Radiation Magnetohydrodynamic Simulations of Protostellar Collapse: Non-Ideal Magnetohydrodynamic Effects and Early Formation of Circumstellar Disks
• Magnetic Fields and Rotations of Protostars
• Effects of Ohmic and ambipolar diffusion on the formation and evolution of the first cores, protostars and circumstellar discs
• The Biermann Battery in Cosmological MHD Simulations of Population III Star Formation
• Formation sites of Population III star formation: The effects of different levels of rotation and turbulence on the fragmentation behavior of primordial gas
• Merge or survive: Number of Population III stars per minihalo
• Turbulent dynamo in a conducting fluid and partially ionized gas
• The Impact of Feedback During Massive Star Formation by Core Accretion
• Magneto-Hydrodynamics of Population III Star Formation
• The impact of the Hall effect during cloud core collapse:implications for circumstellar disk evolution
• Magnetic Prandtl number dependence of kinetic to magnetic dissipation ratio
• The influence of magnetic fields on the thermodynamics of primordial star formation
• Star formation in turbulent molecular clouds with colliding flow
• The First Two Thousand Years of Star Formation
• Magnetic Fields in the Formation of the First Stars. I. Theory vs. Simulation
• Simulating hydromagnetic processes in star formation: introducing ambipolar diffusion into an adaptive mesh refinement code
• Giant protostellar flares: accretion-driven accumulation and reconnection-driven ejection of magnetic flux in protostars
• Magnetic fields in the formation of the first stars.--II Results
• Collapse of turbulent massive cores with ambipolar diffusion and hybrid radiative transfer II. Outflows
• Magnetic field spectrum at cosmological recombination revisited
• Exact shering box solutions of MHD flows with resistivity, viscosity and cooling
• The role of initial magnetic field structure in the launching of protostellar jets
• Primordial magnetic fields in Population III star formation: a magnetised resolution study
• Nonlinear turbulent dynamo during gravitational collapse
• Amplification of turbulence in contracting prestellar cores in primordial minihalos
• On the origin of magnetic fields in stars II: The effect of numerical resolution
• Exponentially amplified magnetic field eliminates disk fragmentation around the Population III protostar
• Impact of magnetic fields on Population III star formation
• Ionization degree and magnetic diffusivity in the primordial star-forming clouds
• Growth of Massive Disk and Early Disk Fragmentation in the Primordial Star Formation
• Magnetic field generation by an inhomogeneous return current
• The Biermann battery driven by a streaming plasma
• Coronal Properties of Low-mass Population III Stars and the Radiative Feedback in the Early Universe
• Saturation level of turbulence in collapsing gas clouds

Cited by in corpus (10)

• Formation of Massive and Wide First-star Binaries in Radiation Hydrodynamics Simulations
• The THESAN-ZOOM project: Population III star formation continues until the end of reionization
• Amplification and saturation of turbulent magnetic field in collapsing primordial gas clouds
• The formation of globular clusters with top-heavy initial mass functions
• Magnetic fields limit the mass of Population III stars even before the onset of protostellar radiation feedback
• Population III star formation in the presence of turbulence, magnetic fields and ionizing radiation feedback
• Effects of chemically homogeneous evolution of the first stars on the 21-cm signal and reionization
• Protostellar disc structure and dynamics during star formation from cloud-scale initial conditions
• Radiation magnetohydrodynamics simulations of Population III star formation during the Epoch of Reionization
• Neural-Network Chemical Emulator for First-Star Formation: Robust Iterative Predictions over a Wide Density Range