@conference {21956, title = {Large-Scale Magnetic Fields in GRB Outflows: Acceleration, Collimation, and Neutron Decoupling}, volume = {727}, year = {2004}, month = {2004/09/1}, pages = {282 - 285}, abstract = {Using ideal magnetohydrodynamics we examine an outflow from a disk surrounding a stellar-mass compact object. We demonstrate that the magnetic acceleration is efficient (\>~ 50\% of the magnetic energy can be transformed into kinetic energy of γ \> 102 baryons) and also that the jet becomes collimated to very small opening angles. Observational implications, focusing on the case of an initially neutron-rich outflow, are discussed in K{\"o}nigl{\textquoteright}s contribution.}, keywords = {95.30.Qd, 98.70.Rz, Astrophysics, Gamma-ray bursts, Gamma-ray sources, Magnetohydrodynamics and plasmas}, isbn = {0094-243X}, url = {https://ui.adsabs.harvard.edu/abs/2004AIPC..727..282V}, author = {Vlahakis, Nektarios and K{\"o}nigl, Arieh} }