Atomic Isotacheia in Epicurus

The Morphology and Surface Brightness of Extragalactic Jets

“…Strong shocks probably manifest themselves in optical and/or infrared and/or X-ray emission and are good candidates for the particle acceleration processes in jet knots which emit at some or all of these frequencies e.g., M-87 (Visvanathan and Pickles 1981and references therein, Smith et al 1983, Stocke et al 1981, Schreier et al 1982 Cen-A (Feigelson et al 1982) 3C31 and 3C66B (Butcher et al 1980) and NGC 7385 (Simkin et al 1983). Such knots may be caused by the Sanders or Norman et al (1982) processes mentioned earlier or by a jet hitting a dense cloud Konigl 1979, Coleman andBicknell 1983).…”

“…There is not enough time here to give an extensive review of all of these papers and in the following I shall mainly concentrate on some of my own recent work. A more detailed account is given in Bicknell (1983) where the relation of my work to the above papers is discussed more fully.…”

“…Several processes have been proposed for particle acceleration in jets and a summary is given in Table 1 below. Benford et al (1980), Eilek (1981), Henriksen et al (1982) Blandford 6, Konigl (1979) Norman et al (1982) Coleman f, Bicknell (1983) The first three processes are stochastic and involve a cascade of turbulent energy to scales smaller than the jet radius. Of the three stochastic candidates in Table 1 Bicknell and Melrose concluded that Fermi acceleration and weak shocks are the most attractive since they dissipate at the largest scale.…”

“…This equation is known to be valid for Fermi acceleration in a relativistic or non-relativistic plasma and weak shocks in a non-relativistic plasma. However, it is probably of much wider validity (see Bicknell 1983). By putting/= Q ,n n !,l3 '' i q(r,z) where n is the relativistic density we can construct turbulent averages and integral equations as before.…”