Abstract:The popular JF12 analytic model by Jansson & Farrar (2012) provides a quantitative description of the Galaxy's large-scale magnetic field, which is widely used in various astrophysical applications. However, both the poloidal X-type component and the spiral disk component of JF12 exhibit regions in which the magnetic divergence constraint is violated. We first propose a cure for this problem, resulting in a truly solenoidal large-scale spiral field. Second, the otherwise straight field lines of the X-type comp… Show more
“…Figure 6 shows the magnetic field in the Galactic center region (central 2 kpc with a height of 300 pc). The field is a combination of the global field first presented by [ 57 ], here used in a modified version [ 58 ], plus a component in the galactic plane presented in [ 59 ]. This combination of fields is necessary, whereas global field models omit the in-plane component in the center.…”
Section: Discussion In the Astrophysical Contextmentioning
confidence: 99%
“… Fig. 6 Three-dimensional view on the magnetic field lines in the Galactic center, using a combination of the global field [ 58 ] and an in-plane Galactic center component [ 59 ] Fig. 7 Mean angle of the field lines with respect to the Galactic plane as a function of the galactocentric radius.…”
Section: Discussion In the Astrophysical Contextmentioning
confidence: 99%
“…7 Mean angle of the field lines with respect to the Galactic plane as a function of the galactocentric radius. The blue line shows the pure global field [ 58 ], the black line shows the combination of [ 58 ] with the Galactic Center field model of [ 59 ] …”
Section: Discussion In the Astrophysical Contextmentioning
confidence: 99%
“… Three-dimensional view on the magnetic field lines in the Galactic center, using a combination of the global field [ 58 ] and an in-plane Galactic center component [ 59 ] …”
Section: Discussion In the Astrophysical Contextmentioning
Cosmic-ray transport in astrophysical environments is often dominated by the diffusion of particles in a magnetic field composed of both a turbulent and a mean component. This process, which is two-fold turbulent mixing in that the particle motion is stochastic with respect to the field lines, needs to be understood in order to properly model cosmic-ray signatures. One of the most important aspects in the modeling of cosmic-ray diffusion is that fully resonant scattering, the most effective such process, is only possible if the wave spectrum covers the entire range of propagation angles. By taking the wave spectrum boundaries into account, we quantify cosmic-ray diffusion parallel and perpendicular to the guide field direction at turbulence levels above 5% of the total magnetic field. We apply our results of the parallel and perpendicular diffusion coefficient to the Milky Way. We show that simple purely diffusive transport is in conflict with observations of the inner Galaxy, but that just by taking a Galactic wind into account, data can be matched in the central 5 kpc zone. Further comparison shows that the outer Galaxy at $$>5$$
>
5
kpc, on the other hand, should be dominated by perpendicular diffusion, likely changing to parallel diffusion at the outermost radii of the Milky Way.
“…Figure 6 shows the magnetic field in the Galactic center region (central 2 kpc with a height of 300 pc). The field is a combination of the global field first presented by [ 57 ], here used in a modified version [ 58 ], plus a component in the galactic plane presented in [ 59 ]. This combination of fields is necessary, whereas global field models omit the in-plane component in the center.…”
Section: Discussion In the Astrophysical Contextmentioning
confidence: 99%
“… Fig. 6 Three-dimensional view on the magnetic field lines in the Galactic center, using a combination of the global field [ 58 ] and an in-plane Galactic center component [ 59 ] Fig. 7 Mean angle of the field lines with respect to the Galactic plane as a function of the galactocentric radius.…”
Section: Discussion In the Astrophysical Contextmentioning
confidence: 99%
“…7 Mean angle of the field lines with respect to the Galactic plane as a function of the galactocentric radius. The blue line shows the pure global field [ 58 ], the black line shows the combination of [ 58 ] with the Galactic Center field model of [ 59 ] …”
Section: Discussion In the Astrophysical Contextmentioning
confidence: 99%
“… Three-dimensional view on the magnetic field lines in the Galactic center, using a combination of the global field [ 58 ] and an in-plane Galactic center component [ 59 ] …”
Section: Discussion In the Astrophysical Contextmentioning
Cosmic-ray transport in astrophysical environments is often dominated by the diffusion of particles in a magnetic field composed of both a turbulent and a mean component. This process, which is two-fold turbulent mixing in that the particle motion is stochastic with respect to the field lines, needs to be understood in order to properly model cosmic-ray signatures. One of the most important aspects in the modeling of cosmic-ray diffusion is that fully resonant scattering, the most effective such process, is only possible if the wave spectrum covers the entire range of propagation angles. By taking the wave spectrum boundaries into account, we quantify cosmic-ray diffusion parallel and perpendicular to the guide field direction at turbulence levels above 5% of the total magnetic field. We apply our results of the parallel and perpendicular diffusion coefficient to the Milky Way. We show that simple purely diffusive transport is in conflict with observations of the inner Galaxy, but that just by taking a Galactic wind into account, data can be matched in the central 5 kpc zone. Further comparison shows that the outer Galaxy at $$>5$$
>
5
kpc, on the other hand, should be dominated by perpendicular diffusion, likely changing to parallel diffusion at the outermost radii of the Milky Way.
“…This includes modifications of the model by Jansson & Farrar [25,26] such as those from refs. [29,30], as well other models for the halo field [24] and the central Galactic zone [28].…”
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