Charge Proportional and Weakly Mass‐Dependent Acceleration of Different Ion Species in the Earth's Magnetotail

Catapano, Filomena; Zimbardo, G.; Perri, S.; Greco, A.; Delcourt, Dominique; Cohen, I. J.

doi:10.1002/2017gl075092

Cited by 10 publications

(17 citation statements)

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“…Journal of Geophysical Research: Space Physics dependent energization and high temporal correlation do not necessarily imply adiabaticity (Catapano et al, 2017;Ukhorskiy et al, 2018). The results from the study presented here cannot determine the dominant mechanism of ion energization in the tail, other than to show that it roughly orders the energization according to E/q.…”

Section: 1029/2020ja028144mentioning

confidence: 55%

“…For example, as noted earlier, ion drift across an ideal flow channel with an enhanced electric field will adiabatically produce charge‐dependent energization and E / q‐ dependent drift trajectories (Mitchell et al, 2018). Test particle simulations of ion interactions with stochastic electromagnetic fluctuations, like those accompanying dipolarization fronts in the magnetotail, have shown primarily charge‐dependent energization with only a small mass dependency (Catapano et al, 2017). Additionally, test particle MHD simulations have suggested that magnetic islands can form within dipolarization fronts and lead to circumferential gradient drifts around the island and nonadiabatic charge‐state‐dependent energization (Ukhorskiy et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

“…In a statistical study of energetic ion enhancements during dipolarizations from GEOTAIL/EPIC/STICS (which can resolve charge state; Williams et al, 1994), Ono et al (2009) found separate cases in which either H + or O + had a harder suprathermal (~10–240 keV) spectrum, or greater energization; this result was hypothesized as being a consequence of turbulent wave frequencies observed to span both H + and O + in situ gyrofrequencies within BBFs. In a test particle simulation of ions interacting with stochastic electromagnetic perturbations within the current sheet, Catapano et al (2017) found that suprathermal ion energization was strongly dependent on and proportional to charge state and only weakly dependent on ion mass (∝ m 1/5 ).…”

Section: Introductionmentioning

confidence: 99%

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Charge‐State‐Dependent Energization of Suprathermal Ions During Substorm Injections Observed by MMS in the Magnetotail

et al. 2020

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Understanding the energization processes and constituent composition of the plasma and energetic particles injected into the near-Earth region from the tail is an important component of understanding magnetospheric dynamics. In this study, we present multiple case studies of the high-energy (≳40 keV) suprathermal ion populations during energetic particle enhancement events observed by the Energetic Ion Spectrometer (EIS) on NASA's Magnetospheric Multiscale (MMS) mission in the magnetotail. We present results from correlation analysis of the flux response between different energy channels of different ion species (hydrogen, helium, and oxygen) for multiple cases. We demonstrate that this technique can be used to infer the dominant charge state of the heavy ions, despite the fact that charge is not directly measured by EIS. Using this technique, we find that the energization and dispersion of suprathermal ions during energetic particle enhancements concurrent with (or near) fast plasma flows are ordered by energy per charge state (E/q) throughout the magnetotail regions examined (~7 to 25 Earth radii). The ions with the highest energies (≳300 keV) are helium and oxygen of solar wind origin, which obtain their greater energization due to their higher charge states. Additionally, the case studies show that during these injections the flux ratio of enhancement is also well ordered by E/q. These results expand on previous results which showed that high-energy total ion measurements in the magnetosphere are dominated by high-charge-state heavy ions and that protons are often not the dominant species above~300 keV.

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Section: 1029/2020ja028144mentioning

confidence: 55%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Charge‐State‐Dependent Energization of Suprathermal Ions During Substorm Injections Observed by MMS in the Magnetotail

et al. 2020

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“…The high E y due to relatively high cross‐tail potential (DiBraccio et al, ; Jasinski et al, ; Slavin et al, , ) would result in strong cross‐tail acceleration for protons at Mercury. The other possible candidate is wave‐particle interactions (e.g., Catapano et al, ; Hasegawa et al, ; Shizgal, ). For the case in Figure , we do observe intense plasma waves with frequencies around the proton gyrofrequency, especially after the dipolarization in the wavelet spectrum of MAG data (see supporting information).…”

Section: Conclusion and Discussionmentioning

confidence: 99%

A Comparative Study of the Proton Properties of Magnetospheric Substorms at Earth and Mercury in the Near Magnetotail

Sun

Slavin

Dewey

et al. 2018

Geophysical Research Letters

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The variations of plasma sheet proton properties during magnetospheric substorms at Earth and Mercury are comparatively studied. This study utilizes kappa distributions to interpret proton properties at both planets. Proton number densities are found to be around an order of magnitude higher, temperatures several times smaller, and κ values broader at Mercury than at Earth. Protons become denser and cooler during the growth phase, and are depleted and heated after the dipolarizations in both magnetospheres. The changes of κ at Earth are generally small (<20%), indicating that spectrum‐preserving processes, like adiabatic betatron acceleration, play an important role there, while variations of κ at Mercury are large (>60%), indicating the importance of spectrum‐altering processes there, such as acceleration due to nonadiabatic cross‐tail particle motions and wave‐particle interactions. This comparative study reveals important intrinsic properties on the energization of protons in both magnetospheres.

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“…First, the finite ion gyroradius effect (which is even more important for heavy ions) results in violation of the adiabaticity in ion motions (Artemyev et al, 2015) and thus can provide mass/charge dependence (Greco et al, 2015). Second, broadband electromagnetic turbulence accompanying the dipolarization fronts (Chaston et al, 2012; Ergun et al, 2015; Kronberg et al, 2019) can locally demagnetize ions and violate adiabatic approximation (Catapano et al, 2017; Greco et al, 2017). Third, combination of ion drifts along the front boundary and gradient drifts in the ambient inhomogeneous field destroys ion trapping and can provide charge‐dependent acceleration (Ukhorskiy et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Juno Observations of Heavy Ion Energization During Transient Dipolarizations in Jupiter Magnetotail

et al. 2020

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Transient magnetic reconnection and associated fast plasma flows led by dipolarization fronts play a crucial role in energetic particle acceleration in planetary magnetospheres. Despite large statistical observations on this phenomenon in the Earth's magnetotail, many important characteristics (e.g., mass or charge dependence of acceleration efficiency and acceleration scaling with the spatial scale of the system) of transient reconnection cannot be fully investigated with the limited parameter range of the Earth's magnetotail. The much larger Jovian magnetodisk, filled by a mixture of various heavy ions and protons, provides a unique opportunity for such investigations. In this study, we use recent Juno observations in Jupiter's magnetosphere to examine the properties of reconnection associated dipolarization fronts and charged particle acceleration. High-energy fluxes of sulfur, oxygen, and hydrogen ions show clear mass-dependent acceleration with energy ∼ m 1/3 . We compare Juno observations with similar observations in the Earth's magnetotail and discuss possible mechanism for the observed ion acceleration.

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Charge Proportional and Weakly Mass‐Dependent Acceleration of Different Ion Species in the Earth's Magnetotail

Cited by 10 publications

References 44 publications

Charge‐State‐Dependent Energization of Suprathermal Ions During Substorm Injections Observed by MMS in the Magnetotail

Charge‐State‐Dependent Energization of Suprathermal Ions During Substorm Injections Observed by MMS in the Magnetotail

A Comparative Study of the Proton Properties of Magnetospheric Substorms at Earth and Mercury in the Near Magnetotail

Juno Observations of Heavy Ion Energization During Transient Dipolarizations in Jupiter Magnetotail

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