Oxygen ion energization by waves  in the high altitude  cusp and mantle

Waara, Martin; Nilsson, Hans; Slapak, Rikard; André, Mats; Stenberg, G.

doi:10.5194/angeo-30-1309-2012

Cited by 5 publications

(6 citation statements)

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“…In the latter case the divergence of the geomagnetic field lines converts the perpendicular energy into the parallel direction which increases the parallel velocity. Several acceleration mechanisms were studied such as parallel potential drops [Lundin et al, 1995;Maggiolo et al, 2006], centrifugal acceleration [Cladis, 1986;Horwitz et al, 1994;Demars et al, 1996;Nilsson et al, 2008Nilsson et al, , 2010Abudayyeh et al, 2015a] and wave-particle interaction [Chang and Coppi, 1981;Chang et al, 1986;Retterer et al, 1987Retterer et al, , 1994; Barakat and Barghouthi, 1994;Barghouthi, 1997;Barghouthi et al, 1998;Bouhram et al, 2004;Barghouthi and Atout, 2006;Barghouthi, 2008;Barghouthi et al, 2011;Slapak et al, 2011;Waara et al, 2011Waara et al, , 2012Abudayyeh et al, 2015b].…”

Section: Journal Of Geophysical Research: Space Physicsmentioning

confidence: 99%

“…If the heating is not sporadic, recent wave activity need not be dominating to maintain the correlation. This relation was studied by Waara et al [2012], and it was found that the correlation exists except at the highest perpendicular temperatures.…”

Section: Wave-particle Interaction (Wpi)mentioning

confidence: 99%

“…with = 1.6 as suggested by Waara et al [2012]. Using this equation, the mean energy per particle due to wave-particle interaction may be calculated.…”

Section: Relative Importance Of Acceleration Mechanismsmentioning

confidence: 99%

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O⁺ and H⁺ above the polar cap: Observations and semikinetic simulations

et al. 2016

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A one‐dimensional direct simulation Monte Carlo model is used to study the outflow of O+ and H+ ions from 1.2 RE to 15.2 RE along two flight trajectories originating from the polar cap, namely, the central polar cap (CPC) and the cusp. To study the effect of varying geophysical conditions and to deduce the proper set of parameters, several parameters were varied, and the results were compared to corresponding data from Cluster spacecraft. First, several sets of diffusion coefficients were considered based on using diffusion coefficients calculated by Barghouthi et al. (1998), Nilsson et al. (2013), and Abudayyeh et al. (2015b) for different altitude intervals. It was found that in the central polar cap using the diffusion coefficients reported by Barghouthi et al. (1998) for altitudes lower than 3.7 RE, zero diffusion coefficients between 3.7 and 7.5 RE and diffusion coefficients from Nilsson et al. (2013) for altitudes higher than 7.5 RE provide the best fit for O+ ions. For O+ ions in the cusp the best fit was obtained for using Barghouthi et al. (1998) diffusion coefficients for altitudes lower than 3.7 RE and Nilsson et al. (2013) diffusion coefficients for altitudes higher than that. The best fit for H+ ions in both regions was obtained by using the diffusion coefficients calculated by Abudayyeh et al. (2015b). Also, it was found that along an ion's trajectory the most recent heating dominates. Second, the strength of centrifugal acceleration was varied by using three values for the ionospheric electric field, namely, 0, 50, and 100 MV/m. It was found that the value of 50 MV/m provided the best fit for both ion species in both regions. Finally, the lower altitude boundary conditions and the electron temperature were varied. Increasing the electron temperature and the lower altitude O+ parallel velocity were found to increase the access of O+ ions to higher altitudes and therefore increase the density at a given altitude. The variation of all other boundary conditions only affected the densities of the ions and not the other moments due to the overwhelming effect of wave‐particle interaction. Furthermore, varying the parameters of one ion species has no effect on the other ion species. We also compared the energy gain per ion due to wave‐particle interaction, centrifugal acceleration, and ambipolar electric field and found that wave‐particle interaction is the most important mechanism, while ambipolar electric field is relatively unimportant especially at higher altitudes.

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Section: Journal Of Geophysical Research: Space Physicsmentioning

confidence: 99%

Section: Wave-particle Interaction (Wpi)mentioning

confidence: 99%

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O⁺ and H⁺ above the polar cap: Observations and semikinetic simulations

et al. 2016

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“…Therefore sporadic heating can explain a region of high temperature and relatively low wave activity. Waara et al [2012] studied this relation and found that there is indeed a correlation except at the highest perpendicular temperatures which indicates that the strongest heating is most likely sporadic. Barghouthi et al [1998] used data from the Plasma Wave Instrument on board Dynamics Explorer 1 (DE-1) to estimate the perpendicular diffusion coefficients in the polar wind for both O + and H + ions.…”

Section: Subject Classificationmentioning

confidence: 99%

“…This is a clear suggestion of further additional energization processes for outflowing O + ions at high altitudes and high latitudes in the dayside polar region. Observations indicated a significant level of electromagnetic turbulence at high altitudes above the polar cap [Gurnett et al 1984, Gurnett and Inan 1988, Waara et al 2012 which suggested an interaction known as wave-particle interaction (WPI) [Chang and Coppi 1981, Chang et al 1986, Retterer et al 1987, Crew et al 1990, Retterer et al 1994, Barghouthi 1997, Barghouthi et al 1998, Bouhram et al 2004, Waara et al 2010, Waara et al 2012]. Field aligned acceleration mechanisms such as field aligned electric fields [Lundin et al 1995, Maggiolo et al 2006] and centrifugal acceleration [Cladis 1986, Horwitz et al 1994, Demars et al 1996, Nilsson et al 2008 were also investigated to explain the energization up to kiloelectronvolt energies of O + ions above the polar cap.…”

Section: Introductionmentioning

confidence: 99%

DE-1 versus Cluster spectral density observations: the effect on ion outflow above the polar cap

Abudayyeh

Barghouthi

Al-Sarsour

et al. 2015

Annals of Geophysics

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<p>Wave-particle interaction is a very important mechanism in describing the outflow of ions at high latitudes and high altitudes. Quasi-linear perpendicular velocity diffusion coefficients are used to describe the effect of wave-particle interactions, therefore it is essential to determine the correct diffusion coefficients that must be used to model the outflow of ions. In this study a Monte Carlo method is used to assess the role of different diffusion coefficients for O+ and H+ ions at high altitudes above the polar cap. Two different sets of diffusion coefficients obtained from Barghouthi [1997]; Barghouthi et al. [1998] and Nilsson et al. [2013] are used. Barghouthi [1997]; Barghouthi et al. [1998] used spectral density measurements from Dynamic Explorer 1 spacecraft (DE-1) observations to calculate the diffusion coefficients, while Nilsson et al. [2013] used spectral density measurements from the Cluster spacecraft to obtain the diffusion coefficients. It was found that diffusion coefficients from Barghouthi [1997]; Barghouthi et al. [1998] in the cusp (aurora) and central polar cap (polar wind) respectively, describe well the observations of ion outflow at altitudes lower than 5 RE, but yield unreasonably high parallel velocities and temperatures at higher altitudes. Also diffusion coefficients from Cluster spectral density measurements produce reasonable results for high altitudes and unreasonably low parallel velocities and temperatures for the low altitude region. Therefore it is suggested that a combination of these diffusion coefficients is used where the diffusion coefficients given by Barghouthi [1997]; Barghouthi et al. [1998] are used at low altitudes and the diffusion coefficients obtained from Cluster measurements are used at high altitudes.</p>

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The Polar Cusp Seen by Cluster

Pitout

Bogdanova

2021

JGR Space Physics

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The investigation of the magnetospheric polar cusps was one of the main objectives of the Cluster mission. The four satellites have crossed those regions numerous times over the years and, with their suitable instrumentation, favorable orbits, and unique multipoint measurements, many aspects of the cusp have been unveiled. The first of those is its highly dynamic nature. With four satellites, whatever their altitude and thus their configuration, the spatial/temporal ambiguity has been lifted and a completely new insight into the motion of the cusp and evolution of the transient small‐scale structures within it was given. Second, the high altitude or exterior cusp, its properties and dynamics, magnetic configuration, the energetic particles observed within, and its boundary with the magnetosheath were characterized in a number of case studies and on a statistical basis. Third, the Cluster cusp observations brought a fresh eye on the reconnection process at the magnetopause, including its location and spatio‐temporal variability. Finally, the complete payload with particle, field and wave detectors have made it possible to treat cusp as a plasma physics laboratory to progress our understanding of wave‐particle interaction and turbulence within the cusp. We have no choice but to note that Cluster has been extremely successful for all these matters.

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Oxygen ion energization by waves in the high altitude cusp and mantle

Cited by 5 publications

References 15 publications

O⁺ and H⁺ above the polar cap: Observations and semikinetic simulations

O⁺ and H⁺ above the polar cap: Observations and semikinetic simulations

DE-1 versus Cluster spectral density observations: the effect on ion outflow above the polar cap

The Polar Cusp Seen by Cluster

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Oxygen ion energization by waves in the high altitude cusp and mantle

Cited by 5 publications

References 15 publications

O+ and H+ above the polar cap: Observations and semikinetic simulations

O+ and H+ above the polar cap: Observations and semikinetic simulations

DE-1 versus Cluster spectral density observations: the effect on ion outflow above the polar cap

The Polar Cusp Seen by Cluster

Contact Info

Product

Resources

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O⁺ and H⁺ above the polar cap: Observations and semikinetic simulations

O⁺ and H⁺ above the polar cap: Observations and semikinetic simulations