Origins of energetic ions in the cusp

Trattner, K. J.; Fuselier, S. A.; Peterson, W. K.; Chang, S.-W.; Friedel, R. H. W.; Aellig, M. R.

doi:10.1029/2000ja003005

Cited by 50 publications

(146 citation statements)

References 50 publications

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“…cusp (Lin et al, 2007) showing these ions have access to the cusp. Further evidence was provided by Trattner et al (2001) who analyzed the ion abundance ratios and concluded these were also consistent with what would be expected with the bow shock. If the quasi-parallel bow shock is the primary source for energetic ions in the cusp and local energization is not occurring, an additional source would have to provide the observed energetic electron or ionospheric ion populations.…”

Section: Introductionmentioning

confidence: 84%

Energetic electrons in the exterior cusp: identifying the source

et al. 2010

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Abstract.A case study is presented to test the role several different sources may play in populating the exterior cusp with energetic (E > 40 keV) electrons. The properties of the electrons measured in the exterior cusp are compared with the expected signatures of three sources in order to weigh the role each source may contribute in populating this region. The potential sources probed are: (1) solar energetic electrons entering the cusp from the solar wind; (2) an equatorial magnetospheric source with particles drifting to high latitudes on the dayside; and (3) a local source accelerating the electrons in situ. From the observations it is likely that local acceleration is the primary source of the energetic electrons in the exterior cusp during this event.

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Section: Introductionmentioning

confidence: 84%

Energetic electrons in the exterior cusp: identifying the source

et al. 2010

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“…The energy range for CEP is from about 20 keV to 10 MeV Fritz et al, 2003). Trattner et al (2001) claimed that the CEPs with energies <150 keV were from the quasi-parallel bow-shock and that while those CEPs with energies >150 keV were from the radiation belt. The present study shows that the 24-44.5 keV CEPs are also not from the bow shock.…”

Section: Introductionmentioning

confidence: 99%

Energetic particle sounding of the magnetospheric cusp with ISEE-1

et al. 2007

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Abstract. Observations on 30October 1978 show the ISEE-1 spacecraft passing though the high-altitude dayside northern magnetospheric cusp region from roughly 16:00 to 18:30 UT, during a slow solar wind period (∼380 km/s). More than two orders of magnitude enhancements of the cusp energetic particle (CEP) fluxes were observed along with a depressed and turbulent local magnetic field. The observed variations of the pitch angle distributions (PAD) provide a unique opportunity to determine the structure of the cusp and the origin of the CEP. Through a boundary sounding technique, the location and orientation of the cusp poleward (or backside) boundary was observed for almost 10 min during which time it appeared initially to be stationary in the GSM/GSE X-direction and then moved sunward about 0.12 Earth radii (R E ). The orientation remained approximately perpendicular to the GSM/GSE X-axis until it was observed to rotate by 60 degrees in ∼3 min before ISEE-1 was fully inside the cusp cavity. The cavity itself was filled with CEP fluxes displaying large anisotropies, indicative of their source being located below (Earthward) of the satellite location. The spacecraft entered from the backside of the cusp, then traveled ∼4 R E through the cavity, and exited through the "top" of the cavity leaving a region of energetic ions below. The PADs demonstrate that the bow shock cannot be the main source of the observed CEPs. The CEP fluxes were measured at about 8.5 h MLT when the IMF had both an 8-10 nT duskward and southward component.

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“…Additionally, Fritz et al (2003) by comparing the time-intensity profiles of O ≤+2 and He ++ ions pointed out that since the seed population of the cusp energetic O ≤+2 is of ionospheric origin, and since the seed population of the cusp energetic He ++ is solar wind plasma, the similarity of their profiles suggests that both seed populations are energized by a common acceleration mechanism active in the polar cusp. Although there are many indications of local particle acceleration in the cusp this view has been questioned I. I. Vogiatzis et al: Supra-thermal particle acceleration in the cusp region 655 by Trattner et al (2001) who provided an alternative explanation for the cusp energetic particles, suggesting that they are accelerated at the quasi-parallel bow shock, then being transported downstream and entering the cusp along newly reconnected field lines or some other solar wind entry mechanism.…”

Section: Introductionmentioning

confidence: 99%

Cluster observations of particle acceleration up to supra-thermal energies in the cusp region related to low-frequency wave activity – possible implications for the substorm initiation process

Vogiatzis

Sarris

et al. 2008

Ann. Geophys.

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Abstract. The purpose of our study is to investigate the way particles are accelerated up to supra-thermal energies in the cusp diamagnetic cavities. For this reason we have examined a number of Cluster cusp crossings, originally identified by Zhang et al. (2005), for the years 2001 and 2002 using data from RAPID, STAFF, EFW, CIS, PEACE, and FGM experiments. In the present study we focus on two particular cusp crossings on 25 March 2002 and on 10 April 2002 which demonstrate in a clear way the general characteristics of the events in our survey. Both events exhibit very sharp spatial boundaries seen both in CNO (primarily single-charged oxygen of ionospheric origin based on CIS observations) and H + flux increases within the RAPID energy range with the magnetic field intensity being anti-correlated. Unlike the first event, the second one shows also a moderate electron flux increase. The fact that the duskward electric field E y has relatively low values <5 mV/m while the local wave activity is very intense provides a strong indication that particle energization is caused primarily by wave-particle interactions. The wave power spectra and propagation parameters during these cusp events are examined in detail. It is concluded that the high ion fluxes and at the same time the presence or absence of any sign of energization in the electrons clearly shows that the particle acceleration depends on the wave power near the local particle gyrofrequency and on the persistence of the wave-particle interaction process before parCorrespondence to: I. I. Vogiatzis (ivogiatz@ee.duth.gr) ticles escape from cusp region. Furthermore, the continuous existence of energetic O + ions suggests that energetic O + populations are of spatial nature at least for the eight events that we have studied so far.

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Origins of energetic ions in the cusp

Cited by 50 publications

References 50 publications

Energetic electrons in the exterior cusp: identifying the source

Energetic electrons in the exterior cusp: identifying the source

Energetic particle sounding of the magnetospheric cusp with ISEE-1

Cluster observations of particle acceleration up to supra-thermal energies in the cusp region related to low-frequency wave activity – possible implications for the substorm initiation process

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