Ambipolar diffusion in self-gravitating filaments

Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany e-mail: HEFroehlich@aip.de

Received: 23 July 2004
Accepted: 10 May 2005

Abstract

One-dimensional similarity solutions for a collapsing, homogeneous, infinitely long cylinder that is subject to ambipolar diffusion are given. There is an analytical solution with infinite density being reached after 4.3 free-fall times. In that case the magnetic field strength B_z on the axis scales like with density ρ . The analytical solution proves “attractive”. Even if the initial conditions depart slightly from those of the analytical solution, that solution is nevertheless approached through damped oscillations.