Dynamic Properties of Particle Injections Inside Geosynchronous Orbit: A Multisatellite Case Study

Motoba, T.; Ohtani, S.; Claudepierre, S. G.; Reeves, G. D.; Ukhorskiy, A. Y.; Lanzerotti, L. J.

doi:10.1029/2020ja028215

Cited by 6 publications

(6 citation statements)

References 62 publications

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“…If a single, deeply penetrating DF (sharp dipolarization) directly drives a dispersionless injection at/inside GEO, the injection region will represent a localized signature in the azimuthal direction. Recently, longitudinally separated multipoint satellite measurements from GOES (Nagai et al., 2019) and Van Allen Probes (Motoba, Ohtani, Claudepierre, et al., 2020) spacecraft provided evidence for azimuthally localized injection regions at/inside GEO.…”

Section: Introductionmentioning

confidence: 99%

Superposed Epoch Analysis of Dispersionless Particle Injections Inside Geosynchronous Orbit

et al. 2021

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Energetic particle injections from Earth's magnetotail-characterized as the sudden flux enhancements of tens to hundreds of keV electrons and/or ions-are one of fundamental signatures of substorm activity in the inner magnetosphere. Fractions of the injected electrons and ions play an important role in building-up Earth's ring current during magnetic storms, providing the seed population for MeV electrons in the outer radiation belt, and introducing the source population responsible for the generation and growth of various plasma waves. How the particles of different species/energies can be transported and/or energized and what controls the penetration of injections inside geosynchronous orbit (GEO) where the magnetic field intensity becomes much stronger are a subject of ongoing debate. The dispersionless character of the flux enhancements-so-called dispersionless injection-is known as a manifestation of the particles that are undergoing either a local energization process or a rapid transport process, or both at/near the leading edge of injections (injection region). In other words, a spacecraft at/near the injection region itself should observe a dispersionless injection, and such in situ measurements would provide an opportunity to understand the underlying mechanisms responsible for the injection.Dispersionless injections are categorized into three types: both-species injections (i.e., coincident injections of both ions (mainly protons, H + ) and electrons (e -)), e --only injections, and H + -only injections. Early energetic particle observations from a LANL spacecraft at GEO provided a statistical picture for the three types of dispersionless injections to occur with local time (or spatial) offsets with respect to midnight (Birn et al., 1997;Thomsen et al., 2001). That is, the e --only (H + -only) injections are preferentially observed ∼2 h after (∼3 h before) local midnight, while the both-species injections occur around midnight. The spatially dependent pattern of the three types has been explained in terms of H + and einjection boundaries that have a dawn-dusk separation and move earthward quasi-stationarily.

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Section: Introductionmentioning

confidence: 99%

Superposed Epoch Analysis of Dispersionless Particle Injections Inside Geosynchronous Orbit

et al. 2021

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“…A lack of coordinated in-situ and context imaging measurements prevents quantitative evaluation of how the energy and mass carried by these flows is redistributed through the inner magnetosphere as they slow and stop. Evidence from multi-spacecraft case studies (Motoba et al, 2020) supports the long-suspected [e.g., Turner et al (2015) and Turner et al (2017)] and references therein connection between BBFs and the particle injections that supply the ring current (Gkioulidou et al, 2014), as well as radiation belt source and seed particles (Jaynes et al, 2015).…”

Section: Objective 3 Science Question 3a: To What Degree Does the Dyn...mentioning

confidence: 70%

“…A network of magnetic field sensors and rapidly refreshing total density maps are required to end long-persistent questions about the flow spatial structure and deceleration in the inner magnetosphere (e.g., Reeves et al, 1996;Wiltberger et al, 2015;Khoo et al, 2018)). A network of energetic electron flux measurements are required to definitively connect flow deceleration with electron injection spatial and temporal evolution, including energy-dependent radial penetration (Li et al, 2011;Turner et al, 2015;Turner et al, 2017;Khoo et al, 2018;Glocer et al, 2020;Motoba et al, 2020;Allison et al, 2021). Embedded within the density image plane, in-situ ground-truth observations are needed.…”

Section: Objective 3 Science Question 3a: To What Degree Does the Dyn...mentioning

confidence: 99%

Plasma Imaging, LOcal Measurement, and Tomographic Experiment (PILOT): A Mission Concept for Transformational Multi-Scale Observations of Mass and Energy Flow Dynamics in Earth’s Magnetosphere

Malaspina

Ergun

Goldstein

et al. 2022

Front. Astron. Space Sci.

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We currently do not understand the fundamental physical processes that govern mass and energy flow through the Earth’s magnetosphere. Knowledge of these processes is critical to understanding the mass loss rate of Earth’s atmosphere, as well as for determining the role that a planetary magnetic field plays in atmospheric retention, and therefore habitability, for Earth-like planets beyond the solar system. Mass and energy flow processes are challenging to determine at Earth in part because Earth’s planetary magnetic field creates a complex “system of systems” composed of interdependent plasma populations and overlapping spatial regions that perpetually exchange mass and energy across a broad range of temporal and spatial scales. Further, the primary mass carrier in the magnetosphere is cold plasma (as cold as ∼0.1 eV), which is invisible to many space-borne instruments that operate in the inner magnetosphere. The Plasma Imaging LOcal and Tomographic experiment (PILOT) mission concept, described here, provides the transformational multi-scale observations required to answer fundamental open questions about mass and energy flow dynamics in the Earth’s magnetosphere. PILOT uses a constellation of spacecraft to make radio tomographic, remote sensing, and in-situ measurements simultaneously, fully capturing cold plasma mass dynamics and its impact on magnetospheric systems over an unprecedented range of spatial and temporal scales. This article details the scientific motivation for the PILOT mission concept as well as a potential mission implementation.

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“…The DFs or magnetic pulses have a duration of tens of seconds or a short time (≤ 4 min) and propagates toward the Earth (e.g., Nakamura et al, 2002;Runov et al, 2009;Tang CL et al, 2010, 2016a. In general, electron injections in the Earth's outer radiation belt are associated with DFs (e.g., Dai L et al, 2015;Turner et al, 2015Turner et al, , 2016Motoba et al, 2020).…”

Section: Discussion and Summarymentioning

confidence: 99%

The 600 keV electron injections in the Earth’s outer radiation belt: A statistical study

Tang¹,

Wang²,

Ni³

et al. 2022

Earth and Planetary Physics

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1. 600 keV electron injections are observed at 4.5 < L < 6.4 under different geomagnetic conditions of 450 nT < AE < 1450 nT.2. Before the electron injections, the flux negative L shell gradient for ≤ 0.6 MeV electrons or the low electron fluxes in the injected region are observed.3. For 600 keV electron injections at different L shells, the source populations from the Earth's 1 plasma sheet are different.

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Dynamic Properties of Particle Injections Inside Geosynchronous Orbit: A Multisatellite Case Study

Cited by 6 publications

References 62 publications

Superposed Epoch Analysis of Dispersionless Particle Injections Inside Geosynchronous Orbit

Superposed Epoch Analysis of Dispersionless Particle Injections Inside Geosynchronous Orbit

Plasma Imaging, LOcal Measurement, and Tomographic Experiment (PILOT): A Mission Concept for Transformational Multi-Scale Observations of Mass and Energy Flow Dynamics in Earth’s Magnetosphere

The 600 keV electron injections in the Earth’s outer radiation belt: A statistical study

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