Modelling the continuous radio outbursts in AE Aquarii

In this paper an attempt is made to simulate the non-thermal radio spectrum of the enigmatic nova-like variable AE Aquarii. Earlier radio studies of AE Aquarii suggested that the radio flares originate from expanding synchrotron-emitting clouds in terms of a van der Laan process. Recent studies also indicate that expanding blob-like propeller-ejected outflow from the system may be the source of the optical flares from AE Aquarii. In this paper we model the radio to infrared flares from AE Aquarii in highly magnetized blob-like propeller-ejected outflow. We showed that the secondary star can possess surface magnetic fields of the order of B(0)greater than or equal to2000 G. Through turbulence and subsequent reconnection, magnetic flux can be pinched off into a fraction of the mass transfer flow from the secondary star. These fields can be highly twisted, resulting in localized regions where the blob plasma is magnetically dominated, i.e. beta=(8pink(B)T/B-2)<1. It was shown that the condition betaless than or equal to1 constrains the frozen-in magnetic field in the blobs to B(blob)greater than or equal to2000 G, which is of the same order of magnitude as the inferred stellar field. The total radio to infrared flare spectrum was modelled in terms of expanding magnetized synchrotron-emitting blobs in various stages of their evolution from rho=(r/r(0)) =1-->400. In terms of our model we consider processes such as magnetic reconnection to provide a fast impulsive injection of 1-2 MeV electrons in regions where the condition for effective acceleration, i.e. betaless than or equal to1, is satisfied. As these blobs expand (rho>1), mechanisms such as shock drift acceleration and magnetic pumping can further energize electrons, in regions where betaless than or equal to1, to energies of the order of gamma-->20. It was shown that the total integrated flux during outbursts, over the frequency range from 1 to 50 000 GHz, can be the result of several (similar to10-20), initially highly magnetized (B(0)similar to2000-3000 G) synchrotron-emitting blobs in different stages of their evolution. The simulated spectrum corresponding to B(0)approximate to2000 G (similar to20 blobs), showed that a peak flux of S(nu)similar to148 mJy is produced at nusimilar to1805 GHz (similar to166 mum), while a spectrum corresponding to B(0)approximate to3000 G (similar to10 blobs), results in a peak synchrotron flux of S(nu)similar to134 mJy at nusimilar to2410 GHz (similar to125 mum). In terms of a multiflare van der Laan superposition, these are obtained where the spectrum changes from a typical self-absorbed S-nu proportional to nu(alpha) to S-nu proportional to nu(-(delta-1)/2) . In terms of the scenarios described above, this may place the latest detection (5sigma level) at nu=3333 GHz (S(nu)approximate to113 mJy), already in the optically thin part of the spectrum.