Journal articles
2021:
- Schober, J.; Brandenburg, A.; Rogachevskii, I.:
“Dynamo instabilities in plasmas with inhomogeneous chiral chemical potential”
(arXiv: 2107.13028) - Schober, J.; Brandenburg, A.; Rogachevskii, I.:
“Production of a chiral magnetic anomaly with emerging turbulence and mean-field dynamo action”
(arXiv: 2107.12945) - Brandenburg, A.; He, Y.; Kahniashvili, T.; Rheinhardt, M.; Schober, J.:
“Gravitational waves from the chiral magnetic effect”
(“The Astrophysical Journal”, Volume 911, 04/2021) - Delvecchio, I.; Daddi, E.; Sargent, M. T.; et al. (incl. Schober, J.) :
“The infrared-radio correlation of star-forming galaxies is strongly M $ _ {\star} $-dependent but nearly redshift-invariant since z $\sim $4”
(“Astronomy & Astrophysics”, Volume 647, 03/2021) - Brandenburg, A.; Johansen, A.; Bourdin, P. A.; et al. (incl. Schober, J.) :
“The Pencil Code, a modular MPI code for partial differential equations and particles: multipurpose and multiuser-maintained”
(“Journal for Open Source Software” (JOSS), Volume 6, 02/2021)
2020:
- Sanati, M., Revaz, Y., Schober, J.; Kunze, K.; Jablonka, P.:
“Constraining the primordial magnetic field with dwarf galaxy simulations”
(“Astronomy & Astrophysics”, Volume 643, 11/2020) - Schober, J.; Fujita, T.; Durrer, R.:
“Generation of chiral asymmetry via helical magnetic fields”
(“Physical Reviews D”; Volume 101; 05/2020)
→ Supplementary data set: github repository - Schober, J.; Brandenburg, A.; Rogachevskii, I.:
“Chiral fermion asymmetry in high-energy plasma simulations”
(“Geophysical & Astrophysical Fluid Dynamics”, Volume 114, 03/2020)
2019:
- Navarrete, F. H.; Schleicher, D. R. G.; Käpylä, P. J.; Schober, J.; Völschow, M.; Mennickent, R. E.:
“Magneto-hydrodynamical origin of eclipsing time variations in post-common-envelope binaries for solar mass secondaries”
(“Monthly Notices of the Royal Astronomical Society, Volume 491, 10/2019) - Schober, J.; Brandenburg, A.; Rogachevskii, I.; Kleeorin, N.:
“Energetics of turbulence generated by chiral MHD dynamos”
(“Geophysical & Astrophysical Fluid Dynamics”, Volume 113, 03/2019)
2018:
- Schober, J.; Rogachevskii, I.; Brandenburg, A.; Boyarsky, A.; Fröhlich, J.; Ruchayskiy, O.; Kleeorin, N.:
“Laminar and turbulent dynamos in chiral magnetohydrodynamics. II. Simulations”
(“The Astrophysical Journal”, Volume 858, Issue 2, 05/2018) - Brandenburg, A.; Schober, J.; Rogachevskii, I.:
“The contribution of kinetic helicity to turbulent magnetic diffusivity”
(“Astronomische Nachrichten”, Volume 338, Issue 7, 01/2018)
2017:
- Brandenburg, A.; Schober, J.; Rogachevskii, I.; Kahniashvili, T.; Boyarsky, A.; Ruchayskiy, O.; Fröhlich, J.; Kleeorin, N.:
“The turbulent chiral-magnetic cascade in the early universe”
(“The Astrophysical Journal Letters”, Volume 845, Issue 2, 08/2017) - Rogachevskii, I.; Ruchayskiy, O.; Boyarsky, A.; Fröhlich, J.; Kleeorin, N.; Brandenburg, A.; Schober, J.:
“Laminar and turbulent dynamos in chiral magnetohydrodynamics. I. Theory”
(“The Astrophysical Journal”, Volume 846, Issue 2, 09/2017) - Schober, J.; Schleicher, D. R. G.; Klessen, R. S.:
“Tracing star formation with non-thermal radio emission”
(“Monthly Notices of the Royal Astronomical Society, Volume 468, Issue 1, 06/2017)
2016:
- Schober, J.; Schleicher, D. R. G.; Klessen, R. S.:
“Galactic synchrotron emission and the FIR-radio correlation at high redshift”
(“The Astrophysical Journal”, Volume 827, Issue 2, 08/2016)
2015:
- Schober, J.; Schleicher, D. R. G.; Federrath, C.; Bovino, S.; Klessen, R. S.:
“Saturation of the turbulent dynamo”
(“Physical Review E”, Volume 92, Issue 2; 08/2015) - Schober, J.; Schleicher, D. R. G.; Klessen, R. S.:
“X-ray emission from star-forming galaxies – Signatures of cosmic rays and magnetic fields”
(“Monthly Notices of the Royal Astronomical Society”, Volume 446, Issue 1, 01/2015)
2014:
- Federrath, C.; Schober, J.; Bovino, S.; Schleicher, D. R. G.:
“The turbulent dynamo in highly compressible supersonic plasmas”
(“The Astrophysical Journal Letters”, Volume 797, Issue 2, 12/2014)
2013:
- Schober, J.; Schleicher, D. R. G. ; Klessen, R. S.:
“Magnetic field amplification in young galaxies”
(“Astronomy & Astrophysics”, Volume 560, 12/2013) - Schleicher, D. R. G.; Latif, M.; Schober, J.; Schmidt, W.; Bovino, S.; Federrath, C.; Niemeyer, J.; Banerjee, R.; Klessen, R. S.:
Magnetic fields during high redshift structure formation
(“Astronomische Nachrichten”, Volume, 334, Issue 6, 06/2013) - Schleicher, D. R. G.; Schober, J.; Federrath, C.; Bovino, S.; Schmidt, W.:
The small-scale dynamo: Breaking universality at high Mach numbers
(“New Journal of Physics”, Volume 15, Issue 2, 02/2013) - Bovino, S.; Schleicher, D. R. G.; Schober, J.:
Turbulent magnetic field amplification from the smallest to the largest magnetic Prandtl numbers: Implications of the turbulent spectra
(“New Journal of Physics”, Volume 15, Issue 1, 01/2013)
2012:
- Schober, J.; Schleicher, D. R. G.; Bovino, S.; Klessen, R. S.:
Small-scale dynamo at low magnetic Prandtl numbers
(“Physical Review E”, Volume 86, Issue 6, 12/2012) - Schober, J.; Schleicher, D. R. G.; Federrath, C.; Glover, S.; Klessen, R. S.; Banerjee, R.:
The small-scale dynamo and non-ideal magnetohydrodynamics in primordial star formation
(“The Astrophysical Journal”, Volume 754, Issue 2, 08/2012) - Schober, J.; Schleicher, D. R. G.; Federrath, C.; Klessen, R. S.; Banerjee, R.:
Magnetic field amplification by small-scale dynamo action: Dependence on turbulence models and Reynolds and Prandtl numbers
(“Physical Review E”, Volume 85, Issue 2, 02/2012)
2011:
- Federrath, C.; Chabrier, G.; Schober, J.; Banerjee, R.; Klessen, R. S.; Schleicher, D. R. G.:
Mach number dependence of turbulent magnetic field amplification: Solenoidal versus compressive flows
(“Physical Review Letters”, Volume 107, Issue 11, 09/2011)
Proceeding articles
- Schober, J.; Schleicher, D. R. G.; Klessen, R. S.:
Tracing star formation with radio emission
(“Francesco’s legacy: star formation in space and time”, 06/2017) - Schober, J.; Schleicher, D. R. G.; Klessen, R. S.; Federrath, C.; Bovino, S.; Glover, S.; Banerjee, R.:
Small-scale dynamo action in primordial halos
(“28th General Assembly of the IAU”, 07/2012) - Schleicher, D. R. G.; Schober, J.; Federrath, C.; Miniati, F.; Banerjee, R.; Klessen, R. S.:
Magnetic fields in the first galaxies: Dynamo amplification and limits from reionization
(‘Magnetic fields in the Universe III: From laboratory and stars to primordial structures”, 10/2011)
Theses
PhD thesis: “On the role of the turbulent dynamo in the evolution of cosmic magnetic fields”
(Abstract)
The aim of this work is to explore the origin of magnetic fields in the Universe. We claim that the turbulent or small-scale dynamo, which amplifies weak seed fields on short timescales in the presence of turbulence, plays an important role in the evolution of cosmic magnetic fields. The theoretical model for the turbulent dynamo is generalized for various astrophysical environments, with a focus on different turbulence spectra. We derive analytical solutions for the dynamo growth rate in the kinematic phase and discuss the subsequent non-linear evolution as well as saturation. In the history of the Universe turbulence is expected to be driven efficiently at the latest during the formation of the first stars and galaxies, where gravitational energy is converted into chaotic motions as the dark matter halos accrete gas from the environment. We model these processes semi-analytically and implement magnetic field amplification by a turbulent dynamo. Our results show that unordered magnetic fields, with strengths comparable to the ones in local galaxies, were already present in the primordial Universe. A potential observational test for magnetic fields in young galaxies is suggested to probe our proposed scenario for the evolution of cosmic magnetic fields.
Diploma thesis: “The small-scale dynamo: Amplification of magnetic fields in the early Universe”
(Abstract)
In this work we explore the small-scale dynamo – a mechanism which may rapidly amplify a week magnetic seed field by converting turbulent kinetic energy into magnetic energy. %The basics for the description of this process are magnetohydrodynamics and turbulence. Both of these theories are presented in this work as far as necessary and available. Moreover, we give an introduction to the theory of magnetohydrodynamical dynamos in general. The small-scale dynamo is described by a theory of Kazantsev, which depends crucially on the nature of turbulence. We propose a model for different types of turbulence and use the Kazantsev theory to determine properties of the small-scale dynamo. With our model we find that the critical magnetic Reynolds number, which needs to be exceeded for small-scale dynamo action, lies between 110 and 2700. Furthermore, we show that the growth rate of the small-scale magnetic field depends strongly on the hydrodynamical Reynolds number Re. In the limit of infinite magnetic Prandtl numbers the growth rate Γ scales between Γ∝Re1/2 and Γ∝Re1/3 for different types of turbulence. For decreasing magnetic Prandtl number, the growth rate of the small-scale dynamo decreases. We apply our model to the magnetic fields in the formation of the first stars. For this we estimate the typical quantities of primordial gas by using a one-zone chemistry code. The resulting small-scale magnetic field reaches its saturation value almost instantly and thus we expect it to be dynamically important in primordial star formation.
