TURBULENCE IN CORONAL MASS EJECTIONS

The magnetic fields measured by the ISEE 3 spacecraft are used to stud y MHD turbulence within coronal mass ejections (CMEs). The spectral in dices of the turbulence inside CMEs are compared with spectral indices found in solar wind undisturbed by CMEs. Irrespective of the CME velo cities, the spectra within CMEs are found to differ from those determi ned for the fast solar wind from coronal holes. Instead, the CME spect ra more closely resemble those found in the slow solar wind. Since bot h CMEs and the plasma sheet are associated with closed magnetic struct ures in. the solar corona, it appears that the turbulence in the solar wind arising from closed coronal regions is fundamentally different f rom the turbulence in wind from coronal holes. Helical properties of m agnetic fields-within CMEs at different scales are studied. Preliminar y results indicate that, in small scales, helical fields are distribut ed in a random fashion with alternating signs of twisting structures. In addition however. CMEs have large-scale helical structures. In the case of the magnetic cloud of day 302, 1978 this structure is interpre ted as a part of the helical structure identified previously by fittin g the data to a force-free flux rope configuration.