Plasmasheet magnetic fields in the distant tail

Plasmasheet Bz and By have been examined for both ISEE‐3 deep tail passes. The plasmasheet Bz component has a relatively strong radial dependence, changing from a primarily northward orientation (Bz = 1.25 ± 1.57 nT, pass 2) at 60‐100 Re to an almost equal north‐south dependence (Bz = −0.20 ± 1.52 nT, pass 2; Bz = 0.22 ± 1.67 nT, pass 4) at 200‐240 Re. The large variances in the field (at all distances) are consistent with the presence of a significant amount of turbulence in the plasmasheet. The level of turbulence is relatively independent of Kp. No apparent relationship is found to exist between By and Bz. At large distances (>200 Re), Bz shows a trend to more negative values with increasing geomagnetic activity. Bz decreases by ∼ 1 nT as Kp increases from 0 to 5. Magnetic reconnection models are discussed in light of the above results.