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Introduction

Flux Transfer Events (FTE) with bipolar Bn signatures, discovered by Russell and Elphic [1978], are identified as reconnected flux tubes resulting from sporadic and localized reconnection. The occurrence of dayside FTEs is strongly correlated with southward magnetosheath fields, consistent with dayside magnetic merging. Both magnetosheath and magnetospheric FTEs contain magnetosphere-like and magnetosheath-like plasmas [Paschmann et al., 1982, Thomsen et al., 1987] and display unique ion composition [Klumpar et al., 1990]. Several regions within FTEs have been identified: the reconnected flux tube and its associated external perturbations [Russell and Elphic, 1978], and, more recently, the fuzzy region between the open flux tube and the external perturbation [Rijnbeek et al., 1987]. Farrugia et al. [1988] defined four distinct nested regions in an FTE: a disturbed magnetospheric region, the plasma mixing region, the magnetosheath-like region (more isotropic and less dense plasma than in the magnetosheath), and the central region where the plasma is indistinguishable from the magnetosheath plasma. These regions are most easily distinguished by the ratio of the plasma to the magnetic field pressure, b . Smith and Owen [1992] found D-shaped ion distributions in magnetosheath-like and central regions of the same event, caused by a parallel velocity cut-off [Cowley, 1982] due to the motion of reconnected field lines with the de Hoffman-Teller velocity.

Lockwood and Hapgood [1997] showed that the transition parameter t defined from the Ne-Te relationship [Hapgood and Bryant, 1990], which organizes the data in the LLBL and within FTEs in the same way, corresponds to the time elapsed since the reconnection of a particular field line. They reproduced ion and electron moments observed by AMPTE-UKS by optimizing the distance to the reconnection site and concluded that the FTE was a result of spacecraft passage through a bulge in the reconnection region.

FTEs studied by Klumpar et. al [1990] do not display a layered structure like the FTE studied by Faruggia et. al [1988]. This fact, along with the absence of dramatic ion flows, led those authors to conclude that structureless FTEs may represent a class of "dead" FTEs, which are no longer connected to the diffusion region or for which active reconnection has ceased. We present here a new intermediate class of events, not active reconnection and not "dead", but Disconnected Magnetosheath Transfer Events (DMTEs). These events observed on Interball Tail in the LLBL evolve with distance from the magnetopause and are considered to be evidence for the penetration of plasma clouds into the magnetosphere [Vaisberg et al., 1997 a, b].



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