Narayan, RameshLi, JasonTchekhovskoy, Alexander2016-04-122009Narayan, Ramesh, Jason Li, and Alexander Tchekhovskoy. 2009. “Stability of Relativistic Force-Free Jets.” The Astrophysical Journal 697 (2) (May 14): 1681–1694. doi:10.1088/0004-637x/697/2/1681.0004-637Xhttp://nrs.harvard.edu/urn-3:HUL.InstRepos:26526402We consider a two-parameter family of cylindrical force-free equilibria, modeled to match numerical simulations of relativistic force-free jets. We study the linear stability of these equilibria, assuming a rigid impenetrable wall at the outer cylindrical radius Rj. Equilibria in which the Lorentz factor γ (R) increases monotonically with increasing radius R are found to be stable. On the other hand, equilibria in which γ (R) reaches a maximum value at an intermediate radius and then declines to a smaller value γj at Rj are unstable. A feature of these unstable equilibria is that poloidal field line curvature plays a prominent role in maintaining transverse force balance. The most rapidly growing mode is an m = 1 kink instability which has a growth rate ∼ (0.4/γj )(c/Rj ). The e-folding length of the equivalent convected instability is ∼2.5γjRj . For a typical jet with an opening angle θj ∼ few/γj , the mode amplitude grows only weakly with increasing distance from the base of the jet. The growth is much slower than one might expect from a naive application of the Kruskal–Shafranov stability criterion.en-USgalaxies: jetsinstabilitiesMHDJournal Article2016-04-1210.1088/0004-637X/697/2/1681