THE EMISSION AND DYNAMICS OF A HEAVY 3-DIMENSIONAL MAGNETIZED JET

A three-dimensional magnetohydrodynamical simulation of a heavy superm agnetosonic magnetized jet has been performed. The jet is precessed at the origin to excite Kelvin-Helmholtz unstable helical modes. The jet exhibits an apparent large amplitude helical twist induced by the pre cession. Twin magnetic filaments accompany an elliptical distortion. T h magnetic filaments twist through 360 degrees over a length scale abo ut twice that required for jet helicity induced by precession to twist through 360 degrees. This organized structure is maintained over cons iderable distance and is associated with a denser jet core that is sur rounded by a less dense sheath consisting of slower moving jet fluid a nd a magnetic field mixed with the external medium.