W. S. Kurth

University of Iowa, Iowa City, Iowa, United States

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Publications (715)2496.88 Total impact

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    ABSTRACT: The in-situ exploration of the magnetospheres of Jupiter and Saturn has revealed different periodic processes. In particular, in the Saturnian magnetosphere, several studies have reported pulsations in the outer magnetosphere with a periodicity of about 1 hour in the measurements of charged particle fluxes, plasma wave, magnetic field strength and auroral emissions brightness. The Low-Energy Magnetospheric Measurement System detector of the Magnetospheric Imaging Instrument (MIMI/LEMMS) on board Cassini regularly detects 1-hour quasi-periodic enhancements in the intensities of electrons with an energy range from a hundred keV to several MeV. We extend an earlier survey of these relativistic electron injections using 10 years of LEMMS observations in addition to context measurements by several other Cassini magnetospheric experiments. The one-year extension of the data and a different method of detection of the injections do not lead to a discrepancy with the results of the previous survey, indicating an absence of a long-term temporal evolution of this phenomenon. We identified 720 pulsed events in the outer magnetosphere over a wide range of latitudes and local times, revealing that this phenomenon is common and frequent in Saturn’s magnetosphere. However, the distribution of the injection events presents a strong local time asymmetry with ten times more events in the duskside than in the dawnside. In addition to the study of their topology, we present a first statistical analysis of the pulsed events properties. The morphology of the pulsations shows a weak local time dependence which could imply a high-latitude acceleration source. We provide some clues that the electron population associated with this pulsed phenomenon is distinct from the field-aligned electron beams previously observed in Saturn’s magnetosphere, but both populations can be mixed. We have also investigated the signatures of each electron injection event in the observations acquired by the Radio and Plasma Wave Science (RPWS) instrument and the magnetometer (MAG). Correlated pulsed signatures are observed in the plasma wave emissions, especially in the auroral hiss, for 12% of the electron injections identified in the LEMMS data. Additionally, in about 20% of the events, such coincident pulsed signatures have been also observed in the magnetic field measurements, some of them being indicative of field-aligned currents. This analysis combined with the multi-instrument approach sets constraints on the origin and significance of the pulsed events. Hence, our results suggest that the acceleration process providing the quasi-periodic relativistic electrons takes place at high-latitudes.
    No preview · Article · Jan 2016 · Icarus
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    ABSTRACT: Over the course of about 6. h on Day 129, 2008, the UV imaging spectrograph (UVIS) on the Cassini spacecraft observed a repeated intensification and broadening of the high latitude auroral oval into the polar cap. This feature repeated at least 5 times with about a 1. h period, as it rotated in the direction of corotation, somewhat below the planetary rotation rate, such that it moved from noon to post-dusk, and from roughly 77° to 82° northern latitudes during the observing interval. The recurring UV observation was accompanied by pronounced ~1. h pulsations in auroral hiss power, magnetic perturbations consistent with small-scale field aligned currents, and energetic ion conics and electrons beaming upward parallel to the local magnetic field at the spacecraft location. The magnetic field and particle events are in phase with the auroral hiss pulsation. This event, taken in the context of the more thoroughly documented auroral hiss and particle signatures (seen on many high latitude Cassini orbits), sheds light on the possible driving mechanisms, the most likely of which are magnetopause reconnection and/or Kelvin Helmholtz waves.
    No preview · Article · Jan 2016 · Icarus
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    ABSTRACT: In this study, we investigate the possibility of nonlinearity in chorus waves during a geomagnetic storm on 1 November 2012. The data we use were measured by the Van Allen Probe B. Wave data and plasmasheet electron data are analyzed. Chorus waves were frequently measured in the morning side during the main phase of this storm. Large amplitude chorus waves were seen of the order of ∼0.6 nT and >7 mV/m, which are similar to or larger than the typical ULF waves. The waves quite often consist of rising tones during the burst sampling. Since the rising tone is known as a signature of nonlinearity, a large portion of the waves are regarded as nonlinear at least during the burst sampling periods. These results underline the importance of nonlinearity in the dynamics of chorus waves. We further compare the measurement and the nonlinear theories, based on the inhomogeneity ratio, our own calculation derived from the field equation, and the backward wave oscillator model. The wave quantities examined are frequency, amplitude, frequency drift rate, and duration. This type of study is useful to more deeply understand wave-particle interactions and hence may lead to predicting the generation and loss of radiation belt electrons in the future.
    No preview · Article · Jan 2016 · Journal of Geophysical Research: Space Physics
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    ABSTRACT: We investigate the importance of electron scattering by magnetosonic waves in the Earth's inner magnetosphere. A statistical survey of the magnetosonic wave amplitude and wave frequency spectrum, as a function of geomagnetic activity, is performed using the Van Allen Probes wave measurements, and is found to be generally consistent with the wave distribution obtained from previous spacecraft missions. Outside the plasmapause the statistical frequency distribution of magnetosonic waves follows the variation of the lower hybrid resonance frequency, but this trend is not observed inside the plasmasphere. Drift and bounce averaged electron diffusion rates due to magnetosonic waves are calculated using a recently developed analytical formula. The resulting time scale of electron energization during disturbed conditions (when AE* > 300 nT) is more than ten days. We perform a 2D simulation of the electron phase space density evolution due to magnetosonic wave scattering during disturbed conditions. Outside the plasmapause, the waves accelerate electrons with pitch angles between 50° and 70°, and form butterfly pitch angle distributions at energies from ~100 keV to a few MeV over a time scale of several days; whereas inside the plasmapause, the electron acceleration is very weak. Our study suggests that intense magnetosonic waves may cause the butterfly distribution of radiation belt electrons especially outside the plasmapause, but electron acceleration due to magnetosonic waves is generally not as effective as chorus wave acceleration.
    No preview · Article · Dec 2015 · Journal of Geophysical Research: Space Physics
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    ABSTRACT: Studies of Saturn's magnetosphere with the Cassini mission have established the importance of Enceladus as the dominant mass source for Saturn's magnetosphere. It is well known that the ionosphere is an important mass source at Earth during periods of intense geomagnetic activity, but lesser attention has been dedicated to study the ionospheric mass source at Saturn. In this paper we describe a case study of data from Saturn's magnetotail, when Cassini was located at ≃ 2200 hours Saturn local time at 36 RS from Saturn. During several entries into the magnetotail lobe, tailward-flowing cold electrons and a cold ion beam were observed directly adjacent to the plasma sheet and extending deeper into the lobe. The electrons and ions appear to be dispersed, dropping to lower energies with time. The composition of both the plasma sheet and lobe ions show very low fluxes (sometimes zero within measurement error) of water group ions. The magnetic field has a swept-forward configuration which is atypical for this region and the total magnetic field strength is larger than expected at this distance from the planet. Ultraviolet auroral observations show a dawn brightening and upstream heliospheric models suggest that the magnetosphere is being compressed by a region of high solar wind ram pressure. We interpret this event as the observation of ionospheric outflow in Saturn's magnetotail. We estimate a number flux between (2.95 ± 0.43) × 109 and (1.43 ± 0.21) × 1010 cm−2s−1, one or about two orders magnitude larger than suggested by steady state MHD models, with a mass source between 1.4 ×102 and 1.1 ×103 kg/s. After considering several configurations for the active atmospheric regions, we consider as most probable the main auroral oval, with associated mass source between 49.7±13.4 and 239.8±64.8 kg/s for an average auroral oval, and 10±4 and 49±23 kg/s for the specific auroral oval morphology found during this event. It is not clear how much of this mass is trapped within the magnetosphere and how much is lost to the solar wind.
    No preview · Article · Dec 2015 · Journal of Geophysical Research: Space Physics
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    ABSTRACT: With attention turned to Europa as a target for exploration, we focus on the space environment in which Europa is embedded. We review remote and in situ observations of plasma properties at Europa's orbit, between Io's dense, UV-emitting plasma torus and Jupiter's dynamic plasma sheet. Where observations are limited (e.g. in plasma composition), we supplement our analysis with models of the neutral and plasma populations from Io to Europa. We evaluate variations and uncertainties in plasma properties with radial distance, latitude, longitude and time.
    Full-text · Article · Oct 2015 · Icarus
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    ABSTRACT: Plasmaspheric hiss plays an important role in controlling the overall structure and dynamics of the Earth's radiation belts. The interaction of plasmaspheric hiss with radiation belt electrons is commonly evaluated using diffusion codes, which rely on statistical models of wave observations that may not accurately reproduce the instantaneous global wave distribution, or the limited in-situ satellite wave measurements from satellites. This paper evaluates the performance and limitations of a novel technique capable of inferring wave amplitudes from low-altitude electron flux observations from the POES spacecraft, which provide extensive coverage in L-shell and MLT. We found that, within its limitations, this technique could potentially be used to build a dynamic global model of the plasmaspheric hiss wave intensity. The technique is validated by analyzing the conjunctions between the POES spacecraft and the Van Allen Probes from September 2012 to June 2014. The technique performs well for moderate-to-strong hiss activity (≥30 pT) with sufficiently high electron fluxes. The main source of these limitations is the number of counts of energetic electrons measured by the POES spacecraft capable of resonating with hiss waves. For moderate-to-strong hiss events, the results show that the wave amplitudes from the EMFISIS instruments onboard the Van Allen Probes are well reproduced by the POES technique, which provides more consistent estimates than the parameterized statistical hiss wave model based on CRRES data.
    Full-text · Article · Oct 2015 · Journal of Geophysical Research: Space Physics
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    ABSTRACT: We use the Cassini Radio and Plasma Wave Science/Langmuir Probe measurements of the electron density from the first 110 flybys of Titan to study how Saturn's magnetosphere influences Titan's ionosphere. The data is first corrected for biased sampling due to varying solar zenith angle (SZA) and solar energy flux (solar cycle effects). We then present results showing that the electron density in Titan's ionosphere, in the altitude range 1600 − 2400 km, is increased by about a factor 2.5 when Titan is located on the nightside of Saturn (Saturn local time (SLT) 21-03 h) compared to when on the dayside (SLT 09-15 h). For lower altitudes (1100 − 1600 km) the main dividing factor for the ionospheric density are the ambient magnetospheric conditions. When Titan is located in the magnetospheric current sheet, the electron density in Titan's ionosphere is about a factor 1.4 higher compared to when Titan is located in the magnetospheric lobes. The factor of 1.4 increase in between sheet and lobe flybys is interpreted as an effect of increased particle impact ionisation from ∼200 eV sheet electrons. The factor of 2.5 increase in electron density between flybys on Saturn's nightside and dayside is suggested to be an effect of the pressure balance between thermal plus magnetic pressure in Titan's ionosphere against the dynamic pressure and energetic particle pressure in Saturn's magnetosphere.
    Full-text · Article · Sep 2015 · Journal of Geophysical Research: Space Physics
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    ABSTRACT: We show the first evidence for locally excited chorus at frequencies below 0.1 fce (electron cyclotron frequency) in the outer radiation belt. A statistical study of chorus during geomagnetic storms observed by the Van Allen Probes found that frequencies are often dramatically lower than expected. The frequency at peak power suddenly stops tracking the equatorial 0.5 fce and f/fce decreases rapidly, often to frequencies well below 0.1 fce (in situ and mapped to equator). These very low frequency waves are observed both when the satellites are close to the equatorial plane and at higher magnetic latitudes. Poynting flux is consistent with generation at the equator. Wave amplitudes can be up to 20 to 40 mV/m and 2 to 4 nT. We conclude that conditions during moderate to large storms can excite unusually low frequency chorus, which is resonant with more energetic electrons than typical chorus, with critical implications for understanding radiation belt evolution.
    No preview · Article · Sep 2015 · Geophysical Research Letters
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    ABSTRACT: We use data from several instruments on board Cassini to determine the characteristics of the plasma and dust regions around Saturn's moon Enceladus. For this we utilize the Langmuir probe and the electric antenna connected to the wideband receiver of the radio and plasma wave science (RPWS) instrument package as well as the magnetometer (MAG). We show that there are several distinct plasma and dust regions around Enceladus. Specifically they are the plume filled with neutral gas, plasma, and charged dust, with a distinct edge boundary region. Here we present observations of a new distinct plasma region, being a dust trail on the downstream side. This is seen both as a difference in ion and electron densities, indicating the presence of charged dust, and directly from the signals created on RPWS antennas by the dust impacts on the spacecraft. Furthermore, we show a very good scaling of these two independent dust density measurement methods over four orders of magnitude in dust density, thereby for the first time cross-validating them. To establish equilibrium with the surrounding plasma the dust becomes negatively charged by attracting free electrons. The dust distribution follows a simple power law and the smallest dust particles in the dust trail region are found to be 10 nm in size as well as in the edge region around the plume. Inside the plume the presence of even smaller particles of about 1 nm is inferred. From the magnetic field measurements we infer strong field-aligned currents at the geometrical edge of Enceladus.
    Full-text · Article · Sep 2015 · Planetary and Space Science
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    ABSTRACT: On or about 2012 August 25, the Voyager 1 spacecraft crossed the heliopause into the nearby interstellar plasma. In the nearly three years that the spacecraft has been in interstellar space, three notable particle and field disturbances have been observed, each apparently associated with a shock wave propagating outward from the Sun. Here, we present a detailed analysis of the third and most impressive of these disturbances, with brief comparisons to the two previous events, both of which have been previously reported. The shock responsible for the third event was first detected on 2014 February 17 by the onset of narrowband radio emissions from the approaching shock, followed on 2014 May 13 by the abrupt appearance of intense electron plasma oscillations generated by electrons streaming outward ahead of the shock. Finally, the shock arrived on 2014 August 25, as indicated by a jump in the magnetic field strength and the plasma density. Various disturbances in the intensity and anisotropy of galactic cosmic rays were also observed ahead of the shock, some of which are believed to be caused by the reflection and acceleration of cosmic rays by the magnetic field jump at the shock, and/or by interactions with upstream plasma waves. Comparisons to the two previous weaker events show somewhat similar precursor effects, although differing in certain details. Many of these effects are very similar to those observed in the region called the "foreshock" that occurs upstream of planetary bow shocks, only on a vastly larger spatial scale. © 2015. The American Astronomical Society. All rights reserved..
    No preview · Article · Aug 2015 · The Astrophysical Journal
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    ABSTRACT: We have analyzed the Cassini Radio and Plasma Wave Science Wideband Receiver (WBR) data specifically looking for the presence of bipolar electrostatic solitary waves (ESWs). Typical examples of these ESWs are provided to show that when they are present, several of them may be detected over a few to several millisecond time span. We carried out an event study of an Enceladus encounter which took place on 9 October 2008. Approximately 30 min prior to and during the crossing of the Enceladus dust plume, several ESWs are observed with amplitudes of about 100 μV/m up to about 140 mV/m, and time durations of several tens of microseconds up to 250 µs. The highest amplitudes (over 10 mV/m) were observed only during the closest approach to Enceladus. We also carried out an ESW survey using the WBR for all years from 2004 to 2008 for distances less than 10 Rs. The survey clearly shows that most of the ESWs are found on the nightside, with a high percentage of them in the range of 4–6 Rs. This location is consistent with the densest part of Saturn's E ring and Enceladus' orbit. These are the first extended survey results of ESWs near Saturn and the first reported ESWs in connection with Enceladus. We discuss possibilities for the generation of these nonlinear ESWs, which involve current, beam, and acoustic, including dust, instabilities.
    No preview · Article · Aug 2015 · Journal of Geophysical Research: Space Physics
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    ABSTRACT: The rotation period of Saturn’s magnetosphere was found to vary with time, and changing periodicities were identified in magnetic fields, radio emissions, and charged particles. Here we analyze the varying period of Saturn kilometric radiation (SKR) from 2009 to early 2013, i.e. mainly after Saturn equinox of August 2009. A periodicity analysis is first applied to the complete SKR signal, and second to SKR intensities separated by spacecraft latitude and wave polarization, attributed to SKR from the northern and southern hemisphere. Our analyses are done with the tracking filter approach of Gurnett et al. (Gurnett et al. [2009a]. Geophys. Res. Lett. 36, L16102) and by simply tracing the phases of normalized SKR intensity maxima (north and south) with time. It is shown that SKR periods from the northern and southern hemisphere converged during 2009, crossed shortly after equinox, and coalesced in spring 2010. We will show that SKR from both hemispheres not only exhibited similar periods, but also similar phases from March 2010 until February 2011 and from August 2011 until June 2012. The in-between time interval (March to July 2011) shows a slowdown of the southern SKR rotation rate and a slight increase in rotation speed for the northern SKR before rotation rates and phases become equal again in August 2011. We also identify SKR signals where the modulation phase deviation exceeds one rotation each time Cassini completes one orbit, i.e. this is consistent with the characteristic of a rotating signal. However, the main SKR modulation signals from 2009 to 2012 can be viewed as being clock-like with no correction needed for the derived periods. A comparison of SKR periodicities after equinox to the planetary period oscillations of the magnetic field shows major differences, and we compare SKR phases to magnetic field phases to explain the deviations.
    No preview · Article · Jul 2015 · Icarus
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    ABSTRACT: We report correlated data on nightside chorus waves and energetic electrons during two small storm periods: 1 November 2012 (Dst≈−45) and 14 January 2013 (Dst≈−18). The Van Allen Probes simultaneously observed strong chorus waves at locations L = 5.8–6.3, with a lower frequency band 0.1–0.5fce and a peak spectral density ∼10−4 nT2/Hz. In the same period, the fluxes and anisotropy of energetic (∼10–300 keV) electrons were greatly enhanced in the interval of large negative interplanetary magnetic field Bz. Using a bi-Maxwellian distribution to model the observed electron distribution, we perform ray tracing simulations to show that nightside chorus waves are indeed produced by the observed electron distribution with a peak growth for a field-aligned propagation approximately between 0.3fce and 0.4fce, at latitude <7°. Moreover, chorus waves launched with initial normal angles either θ<90° or >90° propagate along the field either northward or southward and then bounce back either away from Earth for a lower frequency or toward Earth for higher frequencies. The current results indicate that nightside chorus waves can be excited even during weak geomagnetic activities in cases of continuous injection associated with negative Bz. Moreover, we examine a dayside event during a small storm C on 8 May 2014 (Dst≈−45) and find that the observed anisotropic energetic electron distributions potentially contribute to the generation of dayside chorus waves, but this requires more thorough studies in the future.
    Full-text · Article · Jul 2015 · Journal of Geophysical Research: Space Physics
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    ABSTRACT: Equatorial electron density measurements from the Cassini Radio and Plasma Wave Science experiment are derived from the upper hybrid resonance frequency from Saturn Orbit Insertion (SOI) on 1 July 2004 through 21 May 2013. These densities are used to determine the characteristics of the plasma in the inner magnetosphere of Saturn between the outer edge of the A Ring and the orbit of Enceladus. Electron densities obtained when Cassini first arrived at Saturn on 1 July 2004 showed a plasma distribution decreasing radially outward from Saturn in the direction of Enceladus, the expected distribution of a centrifugally driven plasma expanding radially outward from a source in the main rings. We examine equatorial electron densities in the region between 2.4 and 4.0 Rs and show that the density measurements in this region exhibit a strong seasonal dependence resulting from photon-induced decomposition of icy particles on the ring surfaces, a decomposition process which is controlled by the solar incidence angle. This seasonal dependence will have plasma density implications for Cassini when the spacecraft returns to the region just beyond the A Ring in 2016.
    No preview · Article · Jul 2015 · Journal of Geophysical Research: Space Physics
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    ABSTRACT: Plasmaspheric virtual resonance (PVR) model has been proposed as one of source mechanisms for low-latitude Pi2 pulsations. Since PVR-associated Pi2 pulsations are not localized inside the plasmasphere, simultaneous multipoint observations inside and outside the plasmasphere require to test the PVR model. Until now, however, there are few studies using simultaneous multisatellite observations inside and outside the plasmasphere for understanding the radial structure of Pi2 pulsation. In this study, we focus on the Pi2 event observed at low-latitude Bohyun (BOH, L = 1.35) ground station in South Korea in the postmidnight sector (magnetic local time (MLT) = 3.0) for the interval from 1730 to 1900 UT on 12 March 2013. By using electron density derived from the frequency of the upper hybrid waves detected at Van Allen Probe-A (VAP-A) and Van Allen Probe-B (VAP-B), the plasmapause is identified. At the time of the Pi2 event, VAP-A was outside the plasmasphere near midnight (00:55 MLT and L = ∼6), while VAP-B was inside the plasmasphere in the postmidnight sector (02:15 MLT and L= ∼5). VAP-B observed oscillations in the compressional magnetic field component (Bz) and the dawn-to-dusk electric field component (Ey), having high coherence with the BOH Pi2 pulsation in the H component. The H-Bz and H-Ey cross phases at VAP-B inside the plasmasphere were near −180∘ and −90∘, respectively. These phase relationships among Bz, Ey, and H are consistent with a radially standing oscillation of the fundamental mode reported in previous studies. At VAP-A outside the plasmasphere, Bz oscillations were highly correlated with BOH Pi2 pulsations with ∼−180∘ phase delay, and the H-Ey cross phase is near −90∘. From these two-satellite observations, we suggest that the fundamental PVR mode is directly detected by VAP-A and VAP-B.
    Full-text · Article · Jun 2015 · Journal of Geophysical Research: Space Physics
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    ABSTRACT: In the dawn sector, L~ 5.5 and MLT~4-7, from 01:30 to 06:00 UT during the November 14th 2012 geomagnetic storm, both Van Allen Probes observed an alternating sequence of locally quiet and disturbed intervals with two strikingly different power fluctuation levels and magnetic field orientations: either small (~10−2 nT2) total power with strong GSM Bx and weak By, or large (~10 nT2) total power with weak Bx, and strong By and Bz components. During both kinds of intervals the fluctuations occur in the vicinity of the local ion gyro-frequencies (0.01-10 Hz) in the spacecraft frame, propagate oblique to the magnetic field, (θ ~ 60°) and have magnetic compressibility C = |δB|||/|δB⊥| ∼ 1, where δB|| (δB⊥) are the average amplitudes of the fluctuations parallel (perpendicular) to the mean field. Electric field fluctuations are present whenever the magnetic field is disturbed, and large electric field fluctuations follow the same pattern for quiet and disturbed intervals. Magnetic frequency power spectra at both spacecraft correspond to steep power-laws ∼ f –α with 4 < α < 5 for f ≲ 2 Hz, and 1.1 < α < 1.7 for f ≲ 2 Hz, spectral profiles that are consistent with weak Kinetic Alfvén Waves (KAW) turbulence. Electric power is larger than magnetic power for all frequencies above 0.1 Hz, and the ratio increases with increasing frequency. Vlasov linear analysis is consistent with the presence of compressive KAW with k⊥ρi ≲ 1, right-handed polarization and positive magnetic helicity, in the plasma frame, considering a multi-ion plasma. All these results suggest the presence of weak KAW turbulence which dissipates the energy associated with the intermittent sudden changes in the magnetic field during the main phase of the storm.
    Full-text · Article · Jun 2015 · Journal of Geophysical Research: Space Physics
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    B Cecconi · Philippe Zarka · William S Kurth · DA Gurnett

    Full-text · Technical Report · May 2015
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    B. Cecconi · L. Lamy · Philippe Zarka · Renée Prangé · William S Kurth · P. Louarn

    Full-text · Dataset · May 2015
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    ABSTRACT: Plasmaspheric virtual resonance (PVR) model has been proposed as one of source mechanisms for low-latitude Pi2 pulsations. Since PVR-associated Pi2 pulsations are not localized inside the plasmasphere, simultaneous multipoint observations inside and outside the plasmasphere require to test the PVR model. Until now, however, there are few studies using simultaneous multisatellite observations inside and outside the plasmasphere for understanding the radial structure of Pi2 pulsation. In this study, we focus on the Pi2 event observed at low-latitude Bohyun (BOH, L = 1.35) ground station in South Korea in the postmidnight sector (magnetic local time (MLT) = 3.0) for the interval from 1730 to 1900 UT on 12 March 2013. By using electron density derived from the frequency of the upper hybrid waves detected at Van Allen Probe-A (VAP-A) and Van Allen Probe-B (VAP-B), the plasmapause is identified. At the time of the Pi2 event, VAP-A was outside the plasmasphere near midnight (00:55 MLT and L =∼ 6), while VAP-B was inside the plasmasphere in the postmidnight sector (02:15 MLT and L =∼ 5). VAP-B observed oscillations in the compressional magnetic field component (Bz) and the dawn-to-dusk electric field component (Ey), having high coherence with the BOH Pi2 pulsation in the H component. The H-Bz and H-Ey cross phases at VAP-B inside the plasmasphere were near −180° and −90°, respectively. These phase relationships among Bz, Ey, and H are consistent with a radially standing oscillation of the fundamental mode reported in previous studies. At VAP-A outside the plasmasphere, Bz oscillations were highly correlated with BOH Pi2 pulsations with ∼−180° phase delay, and the H-Ey cross phase is near −90°. From these two-satellite observations, we suggest that the fundamental PVR mode is directly detected by VAP-A and VAP-B.
    Full-text · Article · May 2015 · Journal of Geophysical Research: Space Physics

Publication Stats

11k Citations
2,496.88 Total Impact Points

Institutions

  • 1975-2015
    • University of Iowa
      • Department of Physics and Astronomy
      Iowa City, Iowa, United States
  • 2001-2010
    • Imperial College London
      • Department of Physics
      Londinium, England, United Kingdom
  • 2009
    • Charles University in Prague
      • Faculty of Mathematics and Physics
      Praha, Praha, Czech Republic
  • 2006-2008
    • University of Cologne
      • Institute of Geophysics and Meteorology
      Köln, North Rhine-Westphalia, Germany
    • IST Austria
      Klosterneuberg, Lower Austria, Austria
  • 2005
    • University of Oslo
      • Department of Physics
      Kristiania (historical), Oslo, Norway
    • Université de Versailles Saint-Quentin
      Versailles, Île-de-France, France
  • 1989-2003
    • Johns Hopkins University
      • Applied Physics Laboratory
      Baltimore, Maryland, United States
  • 1983-1988
    • NASA
      • Goddard Space Flight Centre
      Вашингтон, West Virginia, United States
    • University of California, Davis
      • Department of Physics
      Davis, California, United States
  • 1981-1988
    • Pasadena City College
      Pasadena, Texas, United States
  • 1979-1988
    • University of California, Los Angeles
      Los Ángeles, California, United States
  • 1987
    • California Institute of Technology
      • Jet Propulsion Laboratory
      Pasadena, California, United States
  • 1979-1987
    • TRW Automotive
      Ливония, Michigan, United States
  • 1981-1983
    • Massachusetts Institute of Technology
      Cambridge, Massachusetts, United States