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Session: Extragalactic Astronomy and Astrophysics

Name: Mr. Charalampos Sinnis (National & Kapodistrian Univ. of Athens)
Coauthors: No coauthors were included.
Type: Oral
Title: Numerical investigation of instabilities in relativistic magnetized jets
Abstract:

One special trait of astrophysical jets is their enhanced structural stability, as their total length is several times their initial radii. Although we know from previous studies that instabilities develop along their flow, it is not fully understood how they affect the outflow properties. From linear stability analysis, a specific mode has emerged which shows really small growth timescales, comparable to the jet's radius light crossing time. Such small timescales indicate that this mode prevails over almost any other counterpart that have been studied in the literature so far, with a typical value for the timescales of the other modes to be at least ten times higher. This could mean that this "hyper--unstable" solution is capable of changing the initial jet state, even before the rest of the solutions have started to develop. Hence, the study of the non--linear stages of this special mode is imperative. In order to do so, we present relativistic MHD numerical simulations of unperturbed magnetized jet configurations which are able to trigger the "hyper--unstable" solution. Most notably, we observe the formation of a spine--sheath type jet accompanied by vortices that propagate for large distances along the jet. It is really important that we observe the transformation of the initial state of the jet to a new modified configuration which seems to be smooth and stable without any sign of turbulence.