Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Global 3-D Radiation Magnetohydrodynamic Simulations for FU Ori's
  Accretion Disk and Observational Signatures of Magnetic Fields   FU Ori is the prototype of FU Orionis systems which are outbursting
protoplanetary disks. Magnetic fields in FU Ori's accretion disks have
previously been detected using spectropolarimetry observations for Zeeman
effects. We carry out global radiation ideal MHD simulations to study FU Ori's
inner accretion disk. We find that (1) when the disk is threaded by vertical
magnetic fields, most accretion occurs in the magnetically dominated atmosphere
at z$\sim$R, similar to the "surface accretion" mechanism in previous
locally-isothermal MHD simulations. (2) A moderate disk wind is launched in the
vertical field simulations with a terminal speed of $\sim$300-500 km/s and a
mass loss rate of 1-10\% the disk accretion rate, which is consistent with
observations. Disk wind fails to be launched in simulations with net toroidal
magnetic fields. (3) The disk photosphere at the unit optical depth can be
either in the wind launching region or the accreting surface region. Magnetic
fields have drastically different directions and magnitudes between these two
regions. Our fiducial model agrees with previous optical Zeeman observations
regarding both the field directions and magnitudes. On the other hand,
simulations indicate that future Zeeman observations at near-IR wavelengths or
towards other FU Orionis systems may reveal very different magnetic field
structures. (4) Due to energy loss by the disk wind, the disk photosphere
temperature is lower than that predicted by the thin disk theory, and the
previously inferred disk accretion rate may be lower than the real accretion
rate by a factor of $\sim$2-3.

7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex