THE TURBULENT STATE OF COMETARY ION PICKUP GENERATED FLUCTUATIONS NEAR COMET P HALLEY/

One of the principal effects of an outgassing comet is to introduce ad ditional mass into the solar wind flow. This mass-loading process resu lts in the generation of Alfven waves via ion-cyclotron resonance. In the case of the Halley encounter this source of ''new'' fluctuations w as introduced into a low speed solar wind 0.89 AU from the sun. Previo us in situ observations in low speed flows at this distance have descr ibed the fluctuations as turbulently evolved or ''aged.'' The spectral characteristics and time dependent anisotropies of these new cometary fluctuations have been effectively explained by a conservation-of-ene rgy description of the cometary ion pickup process. An alternative des cription has been proposed whereby turbulent cascading generates the o bserved spectrum, implying that the fluctuations evolve significantly in the time between their generation and their observation. Analysis o f the rugged invariants and, in particular, the Alfven ratio suggests that throughout the interaction region upwind from the comet the comet ary ion pickup generated fluctuations became less evolved as the bow s hock was approached. Hence turbulent cascading of the fluctuation ener gy is unlikely to be an effective description of the observations or t o modify the spectral characteristics of these fluctuations significan tly in the upwind interaction region.