Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Stationary equatorial MHD flows in general relativity   We derive a new formulation of the fully general relativistic equations
describing a stationary equatorial MHD outflow from a rotating central object.
The wind solution appears as a level contour of a `Bernoulli' function fixed by
the requirements that it must pass through the slow and fast critical points.
This approach is the general relativistic extension to the classical treatment
of Sakurai (1985). We discuss in details how the efficiency of the magnetic to
kinetic energy conversion depends mainly on the geometry of the flux tubes and
show that the magnetic acceleration can work very well under some conditions.
We show how this tool can be used for the study of several astrophysical
phenomena, among which gamma-ray bursts.

29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas