Probing the magnetic topology of coronal mass ejections by means of Ulysses/HI-SCALE energetic particle observations

Malandraki, O.; Sarris, E. T.; Trochoutsos, P. C.

doi:10.1007/s00585-000-0129-4

Cited by 9 publications

(6 citation statements)

References 27 publications

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“…E > 40 keV electron events have been reported in four ICMEs out to 5.4 AU on the Ulysses spacecraft [Malandraki et al, 2000[Malandraki et al, , 2001, indicating continued solar magnetic connection well beyond 1 AU and including one ICME extending to 4.1 AU well south of the ecliptic at 43°S heliograph latitude. Observed electron BDEs in the ICMEs indicated possible closed loops or reflection from magnetic mirrors formed beyond the spacecraft.…”

Section: Solar Energetic Particles As Probes Of MC or Icme Magnetic Smentioning

confidence: 92%

Solar energetic electron probes of magnetic cloud field line lengths

2011

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[1] Magnetic clouds (MCs) are large interplanetary coronal mass ejections of enhanced and low-variance fields with rotations indicative of magnetic flux ropes originally connected to the Sun. The MC flux rope models require field lines with larger pitch angles and longer lengths with increasing distance from the MC axis. While the models can provide good fits to the in situ solar wind observations, there have not been definitive observational tests of the global magnetic field geometry, particularly for the field line lengths. However, impulsive solar energetic (E > 10 keV) electron events occasionally occur within an MC, and the electron onsets can be used to infer Le, the magnetic field line lengths traveled by the electrons from the Sun to the points in the MC where the electron onsets occur. We selected 8 MCs in and near which 30 solar electron events were observed by the 3DP instrument on the Wind spacecraft. We compared the corresponding Le values with calculated model field line lengths to test two MC models. Some limitations on the technique are imposed by variations of the models and uncertainly about MC boundary locations. We found generally poor correlations between the computed electron path lengths and the model field line lengths. Only one value of Le inside an MC, that of 18 October 1995, exceeded 3.2 AU, indicating an absence of the long path lengths expected in the highly wound outer regions of MC models. We briefly consider the implications for MC models.

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Section: Solar Energetic Particles As Probes Of MC or Icme Magnetic Smentioning

confidence: 92%

Solar energetic electron probes of magnetic cloud field line lengths

2011

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“…Bothmer et al (1996) observed bi-directional and streaming anisotropy suprathermal electron and 0.4-5 MeV ion flux characteristics within two different portions of an ICME detected by ULYSSES, which they interpreted as evidence of closed magnetic loops and open magnetic field lines, respectively. Furthermore, Malandraki et al (2000b) have examined the time evolution of the angular distributions of the solar electron fluxes (E ≥ 42 keV) observed during the passage of two ICMEs over ULYSSES in March 1991. The investigation revealed that both ICMEs presented a filamentary structure comprising magnetic filaments with distinctly different electron anisotropy characteristics.…”

Section: Introductionmentioning

confidence: 99%

Magnetic topology of coronal mass ejection events out of the ecliptic: Ulysses/HI-SCALE energetic particle observations

2003

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Abstract. Solar energetic particle fluxes (E e ≥ 38 keV) observed by the ULYSSES/HI-SCALE experiment are utilized as diagnostic tracers of the large-scale structure and topology of the Interplanetary Magnetic Field (IMF) embedded within two well-identified Interplanetary Coronal Mass Ejections (ICMEs) detected at 56 • and 62 • south heliolatitudes by ULYSSES during the solar maximum southern high-latitude pass. On the basis of the energetic solar particle observations it is concluded that: (A) the high-latitude ICME magnetic structure observed in May 2000 causes a depression in the solar energetic electron intensities which can be accounted for by either a detached or an attached magnetic field topology for the ICME; (B) during the traversal of the out-of-ecliptic ICME event observed in July 2000 energetic electrons injected at the Sun are channeled by the ICME and propagate freely along the ICME magnetic field lines to 62 • S heliolatitude.

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“…At $18:00 UT on this day, the intensities abruptly increase again, in coincidence with a discontinuity in the magnetic field. These simultaneous step discontinuities in the particle intensities and the magnetic field parameters reveal the crossing of barriers separating different particle populations and interplanetary magnetic field regimes (Malandraki et al, 2000;Maia et al, 1998). Fig.…”

Section: In Situ Observationsmentioning

confidence: 91%