A Detection of the Same Hot Plasma in the Corona - During a CME - and Later at Ulysses

We show direct evidence for the same very hot plasma being detected remotely from SOHO in the corona and subsequently, in situ, at Ulysses in the solar wind. This is, to our knowledge, the first time that such an unambiguous identification has been made in the case of hot plasma. This detection complements studies correlating other plasma and field properties observed in situ to the properties measured at the source in the corona. This observation takes advantage of a SOHO-Sun-Ulysses quadrature, during which the Sun-Ulysses included angle is 90^o and it is possible to observe in situ with Ulysses instruments the same plasma that has previously been remotely observed with SOHO instruments in the corona on the limb of the Sun. The identification builds on an existing base of separate SOHO and interplanetary detections of hot plasma. SOHO/UVCS has found evidence for very hot coronal plasma in current sheets in the aftermath of CMEs (Ciaravella et al., 2002; Raymond et al., 2003; Ko et al., 2002) in the [Fe XVIII] λ 974 Å line, implying a temperature on the order of 6 × 10⁶ K. This temperature is unusually high even for active regions, but is compatible with the high temperature predicted in current sheets. In the solar wind, ACE data from early 1998 to middle 2000 revealed high frozen-in Fe charge state (Fe¹⁶⁺)in many cases to be present in interplanetary plasma (Lepri et al., 2004). These identifications were associated with ICMEs. Ciaravella, A., Raymond, J. C., Li, J., Reiser, P., Gardner, L. D., Ko, Y.-K., & Fineschi, S. 2002, Astrophys. J., 575, 1116 Ko, Y.-K., Raymond, J. C., Li, J., Ciaravella, A., Michels, J., Fineschi, S., & Wu, R. 2002, Astrophys. J., 578, 979 Lepri, S. T., & Zurbuchen, T. H. 2004, J. Geophys. Res., 109(A1), A01112 Raymond, J. C., Ciaravella, A., Dobrzycka, D., Strachan, L., Ko, Y.-K., & Uzzo, M. 2003, Astrophys. J., 597, 1106