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Astron. Astrophys. 349, 685-690 (1999)

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5. Summary

Let us reiterate the principal features of the acceleration model presented in this paper.

Because fast magnetic reconnection with [FORMULA] leads to large electric fields in the jet of order [FORMULA] statvolt/cm, just a few reconnecting current sheets are enough to explain the total luminosity of a radio source. It should be kept in mind though that a continuous supply of magnetic energy is required to keep the energy release rate as high as [FORMULA] erg s-1 in a single current sheet. The energy can be supplied if the jet magnetic field is continuously being dragged out from the central rotating source by the jet flow.

A small acceleration length [FORMULA] pc, required for self-consistency of the reconnection process, is naturally predicted since the particles are efficiently ejected from the sheet along the magnetic field lines penetrating the current sheet. This makes the DC electric field acceleration a local mechanism and hence explains constant luminosity all along the jet. The small acceleration length also leads to the acceleration time [FORMULA] s that is much less than the synchrotron loss time [FORMULA] s. Thus the losses in the sheet do not limit the electron energy gain and it is the magnetic field structure in the sheet that determines both the particle orbits and the energy gain. Furthermore, the spatial variation of the magnetic field inside the sheet produces a power-law particle spectrum, and the corresponding temporal evolution of the recently reconnected field lines sets an upper limit on the electron energy gain that is close to the energy [FORMULA] implied by observations.

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© European Southern Observatory (ESO) 1999

Online publication: September 2, 1999