Electron, Proton, and Alpha Monitor on the Advanced Composition Explorer Spacecraft

Gold, R. E.; Krimigis, S. M.; Hawkins, S. E.; Haggerty, D. K.; Lohr, D.; Fiore, E. M.; Armstrong, T. P.; Holland, Glenn E.; Lanzerotti, L. J.

doi:10.1007/978-94-011-4762-0_19

Cited by 117 publications

(117 citation statements)

References 3 publications

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“…The time constant, referred to as rise time t r in the following, is listed in columns 3 and 5 of Table 3. In addition, we characterized the electron anisotropy for all eastern events associated with EIT waves (in 7/22 cases the anisotropies were adopted from Vainio et al (2013)) through a visual inspection of the pitch-angle distributions (PAD) measured by ACE/EPAM (Gold et al, 1998) in the rise phase of the electron event (five-or ten-minute average). Usually this is done in the 0.18 -0.31 MeV channel.…”

Section: Eastern Sep Eventsmentioning

confidence: 99%

Solar Energetic Particles and Associated EIT Disturbances in Solar Cycle 23

et al. 2014

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We explore the link between solar energetic particles (SEPs) observed at 1 AU and large-scale disturbances propagating in the solar corona, named after the Extreme ultraviolet Imaging Telescope (EIT) as EIT waves, which trace the lateral expansion of a coronal mass ejection (CME). A comprehensive search for SOHO/EIT waves was carried out for 179 SEP events during Solar Cycle 23 (1997 -2006). 87 % of the SEP events were found to be accompanied by EIT waves. In order to test if the EIT waves play a role in the SEP acceleration, we compared their extrapolated arrival time at the footpoint of the Parker spiral with the particle onset in the 26 eastern SEP events that had no direct magnetic connection to the Earth. We find that the onset of proton events was generally consistent with this scenario. However, in a number of cases the first near-relativistic electrons were detected too early. Furthermore, the electrons had in general only weakly anisotropic pitch-angle distributions. This poses a problem for the idea that the SEPs were accelerated by the EIT wave or in any other spatially confined region in the low corona. The presence of weak electron anisotropies in SEP events from the eastern hemisphere suggests that transport processes in interplanetary space, including cross-field diffusion, play a role in giving the SEPs access to a broad range of helio-longitudes.

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Section: Eastern Sep Eventsmentioning

confidence: 99%

Solar Energetic Particles and Associated EIT Disturbances in Solar Cycle 23

et al. 2014

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“…In this paper, we use measurements of the angular distributions of the intensities of energetic electrons in the energy range 42 -290 keV detected by the sunward looking telescope LEFS60 and the antisunward looking telescope LEFS150 of the EPAM experiment (Electron, Proton, and Alpha Monitor) on board ACE. The EPAM experiment (the flight spare of the Ulysses HI-SCALE instrument) has been described in full detail by Gold et al [1998]. We also use 1.9-4.8 MeV ion data from the LEMS120 ion telescope.…”

Section: Instrumentationmentioning

confidence: 99%

“…The spacecraft spin axis is directed within 20°F igure 1. One minute averaged differential intensities of 38-315 keV electrons and 1.9-4.8 MeV ions measured by the B detector of the CA60 telescope and the LEMS120 ion telescope, respectively, of the EPAM experiment on board ACE [Gold et al, 1998]. The solid vertical lines indicate the passage of the shocks S1 and S2, and the black horizontal bars indicate the passage of interplanetary coronal mass ejections (ICMEs) as identified by Skoug et al [2004].…”

Section: Instrumentationmentioning

confidence: 99%

“…The black triangle in the fourth panel identifies the period with the highest (68 nT) magnetic field magnitude. (right panels) The 64 -112 keV electron pitch-angle distributions (PADs) measured by the LEFS60 and LEFS150 telescopes of the EPAM instrument [Gold et al, 1998]. (bottom panels) The 1.9-4.8 MeV ion PAD snapshots as observed by the eight sectors of the LEMS120 telescope.…”

Section: First Icme 29-30 October 2003mentioning

confidence: 99%

“…After snapshot III the magnetic field direction was such that the LEMS120 telescope Figure 4. The 64 -112 keV electron and 1.9-4.8 MeV ion pitch-angle distributions measured by the LEFS60, LEFS150, and LEMS120 telescopes of the EPAM instrument [Gold et al, 1998] at different times during the passage (and in the vicinity) of the second ICME. Figure 3.…”

Section: Second Icme 31 October To 2 November 2003mentioning

confidence: 99%

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October/November 2003 interplanetary coronal mass ejections: ACE/EPAM solar energetic particle observations

et al. 2005

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[1] In late October and early November 2003 the ACE spacecraft at 1 AU detected two shock-associated interplanetary coronal mass ejections (ICMEs). In the sheath region formed in front of both ICMEs, some of the highest speeds ever directly measured in the solar wind were observed. We analyze in detail the energetic particle signatures measured at 1 AU by the EPAM experiment on board ACE during the passage and in the vicinity of these ICMEs. Solar energetic particles (SEPs) are utilized as diagnostic tracers of the large-scale structure and topology of the interplanetary magnetic field (IMF) embedded within both ICME events. In order to explain the bidirectional particle flows observed within both ICMEs, we have examined two candidate scenarios for these ICMEs in terms of open and closed magnetic field configurations. In the context of an open field configuration, the enhanced magnetic field regions associated with the CME-driven shocks mirror the energetic particles and hence the observed bidirectional flows. In the context of a closed field configuration, bidirectional flows result from particle circulation and reflection in a looped field configuration. Furthermore, we use the ACE/EPAM observations to reassess the leading and trailing boundaries of the ICMEs with respect to those previously proposed based upon ACE/SWEPAM solar wind plasma, suprathermal electron measurements, and ACE/MAG magnetic field data.

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Influence of interplanetary coronal mass ejections on the peak intensity of solar energetic particle events

Lario

Karelitz

2014

JGR Space Physics

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We study whether the presence of coronal mass ejections (CMEs) in interplanetary space (ICMEs) affects the maximum intensity of solar energetic particle (SEP) events. We compute the maximum intensity of 175-315 keV electron and 9-15, 15-40, and 40-80 MeV proton fluxes measured during the prompt component of 147 western SEP events observed near Earth throughout solar cycle 23. When using in situ observations to determine the presence and location of preceding ICMEs during SEP events, we find that, over the ensemble of events, those observed either within a preceding ICME or when a preceding ICME is beyond the observer's location have, on average, larger peak intensities than the events observed in absence of ICMEs. The few events observed when an Earth-directed ICME is located between the Sun and the observer tend to have lower 9-15 and 15-40 MeV proton peak intensities than the events without preceding ICMEs; the differences are not significant for 175-315 keV electron peak intensities. When using coronagraph observations to determine the presence of preceding CMEs, we find that, over the ensemble of events, those events (Case P) occurring within 24 h after the launch of a CME from the same active region as the primary CME generating the SEP event tend to have higher peak intensities than those events (Case NP) occurring without a preceding CME. The differences between the average peak intensities of these two event cases (P and NP) are smaller when we exclude events observed when a prior ICME is already located at or beyond Earth.

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Electron, Proton, and Alpha Monitor on the Advanced Composition Explorer Spacecraft

Cited by 117 publications

References 3 publications

Solar Energetic Particles and Associated EIT Disturbances in Solar Cycle 23

Solar Energetic Particles and Associated EIT Disturbances in Solar Cycle 23

October/November 2003 interplanetary coronal mass ejections: ACE/EPAM solar energetic particle observations

Influence of interplanetary coronal mass ejections on the peak intensity of solar energetic particle events

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