Its true that most of the angular momentum in the solar system is in the planets (mostly Jupiter). Its also true that magnetic fields and plasma effects are a dominant driver of angular momentum transport and other dynamics in most accretion disks.
Its implausible that the magnetic fields played the dominant role in the angular momentum profiles in the planets themselves. You can determine ionization fractions in protoplanetary disks due to external irradiation, cosmic ray penetration, and radioactive decay of elements internal to the disk structure which in turn sets the coupling of the neutrals to the magnetic field (mediated by collisions with the ions and electrons, details in first source below). The coupling between the magnetic field and neutrals in protoplanetary disks is strong interior to 1 AU and past ~100 AU but intermediate to the regions (where planet formation occurs) you most likely get MHD quiet zones (where the B field is not a dominant driver).
On global scales the magnetic field probably moves the angular momentum in the gas of the disk around but in planet forming regions the dynamics are most likely mediated by the specific microphysics of planet formation i.e. streaming instabilities, gravitational instabilities, coagulation, oligarchic growth, transport of angular momentum via lindblad resonances, etc.
In short, the dominance of the magnetic field on the motion of the neutrals appears to be too weak in planet forming regions for magnetic fields to locally control the formative dynamics.
Protoplanetary disks remain a troubling area in astrophysics where the process by which angular momentum transport is not well determined because it lacks the coupling of the global field to the neutrals that probably does determine it in other disks such as cataclysmic variables, AGNs, SXTs, etc.
This is the present word on magnetic field interaction in protoplanetary disks
http://xxx.lanl.gov/pdf/0906.0854
General background on angular momentum transport in disks
http://www.lra.ens.fr/~balbus/araa.pdf
The other problem is with the idea of strong fields, those aren't good for redistributing angular momentum radially as they tend to enforce rigid rotation profiles which is bad because it generates a configuration wherein angular momentum transport is greatly inhibited. Strong fields are good for vertical angular momentum transport along filed lines out of the disk plane via winds, or azimuthal field lines near the central source via jets but these phenomenon are not generally in regions where planet formation is likely to be occurring actively and might be more disruptive than beneficial if they were.
You actually want (and have outside of regions near central sources permeated by strong dipole fields) weaker fields.
Its true that most of the angular momentum in the solar system is in the planets (mostly Jupiter). Its also true that magnetic fields and plasma effects are a dominant driver of angular momentum transport and other dynamics in most accretion disks.
Its implausible that the magnetic fields played the dominant role in the angular momentum profiles in the planets themselves. You can determine ionization fractions in protoplanetary disks due to external irradiation, cosmic ray penetration, and radioactive decay of elements internal to the disk structure which in turn sets the coupling of the neutrals to the magnetic field (mediated by collisions with the ions and electrons, details in first source below). The coupling between the magnetic field and neutrals in protoplanetary disks is strong interior to 1 AU and past ~100 AU but intermediate to the regions (where planet formation occurs) you most likely get MHD quiet zones (where the B field is not a dominant driver).
On global scales the magnetic field probably moves the angular momentum in the gas of the disk around but in planet forming regions the dynamics are most likely mediated by the specific microphysics of planet formation i.e. streaming instabilities, gravitational instabilities, coagulation, oligarchic growth, transport of angular momentum via lindblad resonances, etc.
In short, the dominance of the magnetic field on the motion of the neutrals appears to be too weak in planet forming regions for magnetic fields to locally control the formative dynamics.
Protoplanetary disks remain a troubling area in astrophysics where the process by which angular momentum transport is not well determined because it lacks the coupling of the global field to the neutrals that probably does determine it in other disks such as cataclysmic variables, AGNs, SXTs, etc.
This is the present word on magnetic field interaction in protoplanetary disks http://xxx.lanl.gov/pdf/0906.0854
General background on angular momentum transport in disks http://www.lra.ens.fr/~balbus/araa.pdf
The other problem is with the idea of strong fields, those aren't good for redistributing angular momentum radially as they tend to enforce rigid rotation profiles which is bad because it generates a configuration wherein angular momentum transport is greatly inhibited. Strong fields are good for vertical angular momentum transport along filed lines out of the disk plane via winds, or azimuthal field lines near the central source via jets but these phenomenon are not generally in regions where planet formation is likely to be occurring actively and might be more disruptive than beneficial if they were.
You actually want (and have outside of regions near central sources permeated by strong dipole fields) weaker fields.