Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Use of incident and reflected solar particle beams to trace the topology of magnetic clouds
AU - Tan, Lun C.
AU - Malandraki, Olga E.
AU - Reames, Donald V.
AU - Ng, Chee K.
AU - Wang, Linghua
AU - Dorrian, Gareth
PY - 2012/5/10
Y1 - 2012/5/10
N2 - Occasionally, large solar energetic particle (SEP) events occur inside magnetic clouds (MCs). In this work, the onset time analysis, the peak intensity analysis, and the decay phase analysis of SEPs are used to investigate two large SEP events inside MCs: the 1998 May 2 and 2002 April 21 events. The onset time analysis of non-relativistic electrons and similar to MeV nucleon(-1) heavy ions shows the stability of the magnetic loop structure during a period of a few hours in the events examined. The joint analysis of pitch-angle distributions and peak intensities of electrons exhibits that, depending on the particle pitch angle observed at 1 AU, in the April event the reflection point of particles may be distributed along a wide spatial range, implying that the magnetic loop is a magnetic bottle connected to the Sun with both legs. In contrast, in the May event particle reflection occurs abruptly at the magnetic mirror formed by a compressed field enhancement behind the interplanetary shock, consistent with its open field line topology.
AB - Occasionally, large solar energetic particle (SEP) events occur inside magnetic clouds (MCs). In this work, the onset time analysis, the peak intensity analysis, and the decay phase analysis of SEPs are used to investigate two large SEP events inside MCs: the 1998 May 2 and 2002 April 21 events. The onset time analysis of non-relativistic electrons and similar to MeV nucleon(-1) heavy ions shows the stability of the magnetic loop structure during a period of a few hours in the events examined. The joint analysis of pitch-angle distributions and peak intensities of electrons exhibits that, depending on the particle pitch angle observed at 1 AU, in the April event the reflection point of particles may be distributed along a wide spatial range, implying that the magnetic loop is a magnetic bottle connected to the Sun with both legs. In contrast, in the May event particle reflection occurs abruptly at the magnetic mirror formed by a compressed field enhancement behind the interplanetary shock, consistent with its open field line topology.
KW - Sun: heliosphere
KW - ELECTRON EVENTS
KW - FIELD LINES
KW - CORONAL MASS EJECTION
KW - SHOCK
KW - WIND SPACECRAFT
KW - ACCELERATION
KW - TRANSPORT
KW - DISTRIBUTIONS
KW - Sun: magnetic topology
KW - ENERGETIC PARTICLES
KW - PITCH-ANGLE
KW - Sun: coronal mass ejections (CMEs)
KW - Sun: particle emission
U2 - 10.1088/0004-637X/750/2/146
DO - 10.1088/0004-637X/750/2/146
M3 - Journal article
VL - 750
JO - The Astrophysical Journal
JF - The Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 146
ER -