Energetic electron response to ULF waves induced by interplanetary shocks in the outer radiation belt

Zong, Qiugang; Zhou, X.‐Z.; Wang, Y. F.; Li, X.; Song, P.; Baker, D. N.; Fritz, T. A.; Daly, P. W.; Dunlop, M. W.; Pedersen, Å.

doi:10.1029/2009ja014393

Cited by 300 publications

(455 citation statements)

References 61 publications

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“…As shown in Figures 4e and 4f, the magnetic field (blue) and electric field (red) exhibit phase differences of 90°for both wave modes, suggesting they are standing waves along the magnetic field lines [Singer et al, 1982]. Using the stretched string model, the observed poloidal and toroidal waves are determined as the fundamental modes [e.g., Zong et al, 2009]. The results from SC4 between 1610 and 1650 UT are shown in Figures 4g-4l, in the same format as those from SC1.…”

Section: Event A: 25 October 2002mentioning

confidence: 99%

“…Although the acceleration/deceleration effect on the O + ions at tens of keV might be weak and not as significant as the radiation belt electrons in terms of drift resonance [e.g., Zong et al, 2009], the active role of the ULF standing waves on the dynamic of ring current O + ions could not be omitted. Due to resonant interactions, the wave amplitudes should be decaying in event A and growing in event B.…”

Section: Comparison With Previous Studiesmentioning

confidence: 99%

“…Due to the comparable periods between the ULF waves and the particle drift motions (radiation belt electrons)/bounce motions (ring current ions, background ion population), drift resonance or drift-bounce resonance can be excited and results in the energy transfer between the waves and particles [e.g., Elkington et al, 2003;Ozeke and Mann, 2008]. With the data from the Cluster mission, observational studies of the drift resonance between the radiation belt electrons and the ULF standing waves with periods of several minutes (Pc5 range) have been recently reported [Zong et al, 2007[Zong et al, , 2009Yang et al, 2010]. These studies confirmed the active role of ULF standing waves in accelerating the electrons.…”

Section: Introductionmentioning

confidence: 99%

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The role of ULF waves interacting with oxygen ions at the outer ring current during storm times

Yang

Zong

et al. 2011

J. Geophys. Res.

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[1] The modulations of the outer ring current O + ion fluxes by ULF Pc5 waves are investigated by multisatellite observations during storm times. The O + ions have energies up to tens of keV. We concentrate on the process in terms of drift-bounce resonance of O + ions with ULF standing waves to understand whether the ring current O + ions could be accelerated/decelerated by ULF waves. Two case studies are performed, in which the Cluster satellites travel the outer ring current region in the morning sector with radial distances of about 5.5 R E . Distinct O + ion flux oscillations are observed associated with fundamental mode ULF standing waves. On 25 October 2002, both satellites SC1 and SC4 observe strong poloidal and toroidal standing waves at approximately the same region one by one with a time lag of 45 min. The O + ion flux oscillations at around 20 keV are dominantly coherent with the poloidal standing wave at 3.4 mHz with cross phases of near 90°with respect to the magnetic field waves. The O + phase space density spectra at 10 to 25 keV, measured by both satellites, deviate significantly from the typical power law distribution. We suggest that the O + ions at 10 to 25 keV are accelerated due to drift-bounce resonance with the poloidal standing wave. On 4 November 2002, satellite SC1 observes considerable poloidal and toroidal standing waves. The O + ion flux oscillation at around 7 keV is well correlated with both of the two wave modes at 3.7 mHz with cross phases of about 90°with respect to the magnetic field waves. The O + spectra at 4 to 8 keV deviates remarkably from the background power law distribution. When satellite SC4 closely encounters the same region 40 min later, the wave activities at 3.7 mHz are found to be rather weak and the O + spectra is close to the background power law distribution. We suggest that the spectra variation of SC1 results from the deceleration of O + ion at 4 to 8 keV via drift-bounce resonances during the strong wave activities. The observations made in this study reveal the effective role of ULF standing waves in accelerating/decelerating the ring current O + ions.Citation: Yang, B., Q.-G. Zong, S. Y. Fu, X. Li, A. Korth, H. S. Fu, C. Yue, and H. Reme (2011), The role of ULF waves interacting with oxygen ions at the outer ring current during storm times,

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Section: Event A: 25 October 2002mentioning

confidence: 99%

Section: Comparison With Previous Studiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The role of ULF waves interacting with oxygen ions at the outer ring current during storm times

Yang

Zong

et al. 2011

J. Geophys. Res.

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“…Such large fluxes of anisotropic suprathermal electrons can be expected to account for the generation of intense chorus waves in the duskside, similar to the situation in the nightside [e.g., Li et al, 2009b]. The short-timescale (several minutes) variation of electron pitch angle distribution, particularly at high energies (E k ≥ 31 keV), was produced by the modulation of ULF wave-associated electric fields [e.g., Zong et al, 2009]. The long-timescale (tens minutes to hours) decay of electron differential fluxes was primarily caused by the drift of the newly injected population.…”

Section: Introductionmentioning

confidence: 99%

Intense duskside lower band chorus waves observed by Van Allen Probes: Generation and potential acceleration effect on radiation belt electrons

Zhu

Xiao

et al. 2014

JGR Space Physics

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Local acceleration driven by whistler mode chorus waves largely accounts for the enhancement of radiation belt relativistic electron fluxes, whose favored region is usually considered to be the plasmatrough with magnetic local time approximately from midnight through dawn to noon. On 2 October 2013, the Van Allen Probes recorded a rarely reported event of intense duskside lower band chorus waves (with power spectral density up to 10 −3 nT 2 ∕Hz) in the low-latitude region outside of L = 5. Such chorus waves are found to be generated by the substorm-injected anisotropic suprathermal electrons and have a potentially strong acceleration effect on the radiation belt energetic electrons. This event study demonstrates the possibility of broader spatial regions with effective electron acceleration by chorus waves than previously expected. For such intense duskside chorus waves, the occurrence probability, the preferential excitation conditions, the time duration, and the accurate contribution to the long-term evolution of radiation belt electron fluxes may need further investigations in future.

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“…Solar wind upstream waves may also directly enter near the equatorial noon subsolar point or the high latitude cusp regions (Kessel et al, 2004, and references therein). ULF wave excitation is also caused by sudden impulses (solar wind pressure pulses) on the magnetosphere (Southwood and Kivelson, 1990;Zong et al, 2009;Sarris et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

ULF wave activity during the 2003 Halloween superstorm: multipoint observations from CHAMP, Cluster and Geotail missions

Balasis

Daglis

Zesta³

et al. 2012

Ann. Geophys.

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Abstract. We examine data from a topside ionosphere and two magnetospheric missions (CHAMP, Cluster and Geotail) for signatures of ultra low frequency (ULF) waves during the exceptional 2003 Halloween geospace magnetic storm, when Dst reached ∼ −380 nT. We use a suite of waveletbased algorithms, which are a subset of a tool that is being developed for the analysis of multi-instrument multi-satellite and ground-based observations to identify ULF waves and investigate their properties. Starting from the region of topside ionosphere, we first present three clear and strong signatures of Pc3 ULF wave activity (frequency 15-100 mHz) in CHAMP tracks. We then expand these three time intervals for purposes of comparison between CHAMP, Cluster and Geotail Pc3 observations but also to be able to search for Pc4-5 wave signatures (frequency 1-10 mHz) into Cluster and Geotail measurements in order to have a more complete picture of the ULF wave occurrence during the storm. Due to the fast motion through field lines in a low Earth orbit (LEO) we are able to reliably detect Pc3 (but not Pc4-5) waves from CHAMP. This is the first time, to our knowledge, that ULF wave observations from a topside ionosphere mission are compared to ULF wave observations from magnetospheric missions. Our study provides evidence for the occurrence of a number of prominent ULF wave events in the Pc3 and Pc4-5 bands during the storm and offers a platform to study the wave evolution from high altitudes to LEO. The ULF wave analysis methods presented here can be applied to observations from the upcoming Swarm multi-satellite mission of ESA, which is anticipated to enable joint studies with the Cluster mission.

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Energetic electron response to ULF waves induced by interplanetary shocks in the outer radiation belt

Cited by 300 publications

References 61 publications

The role of ULF waves interacting with oxygen ions at the outer ring current during storm times

The role of ULF waves interacting with oxygen ions at the outer ring current during storm times

Intense duskside lower band chorus waves observed by Van Allen Probes: Generation and potential acceleration effect on radiation belt electrons

ULF wave activity during the 2003 Halloween superstorm: multipoint observations from CHAMP, Cluster and Geotail missions

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