The effective acceleration of plasma outflow in the paraboloidal magnetic field |
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| Authors: | V S Beskin E E Nokhrina |
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| Institution: | P. N. Lebedev Physical Institute, Leninsky Prosp., 53, Moscow, 119991, Russia;Moscow Institute of Physics and Technology, Dolgoprudny, Moscow region, 141700, Russia |
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| Abstract: | The problem of the efficiency of particle acceleration for a paraboloidal poloidal magnetic field is considered within the approach of steady axisymmetric magnetohydrodynamic (MHD) flow. For the large Michel magnetization parameter σ it is possible to linearize the stream equation near the force-free solution and to solve the problem self-consistently as was done by Beskin, Kuznetsova & Rafikov for a monopole magnetic field. It is shown that, on the fast magnetosonic surface (FMS), the particle Lorentz factor γ does not exceed the standard value σ1/3 . On the other hand, in the supersonic region, the Lorentz factor grows with the distance z from the equatorial plane as γ≈ ( z / R L)1/2 up to the distance z ≈σ2 R L , where R L= c /ΩF is the radius of the light cylinder. Thus, the maximal Lorentz factor is γmax≈σ , which corresponds to almost the full conversion of the Poynting energy flux into the particle kinetic one. |
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| Keywords: | MHD galaxies: jets |
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