A Case Study on the Origin of Near‐Earth Plasma

Glocer, A.; Welling, D. T.; Chappell, C. R.; Tóth, G.; Fok, M. C. H.; Komar, C. M.; Kang, Seungbum; Buzulukova, N.; Ferradas, C.; Bingham, S.; Mouikis, C.

doi:10.1029/2020ja028205

Cited by 37 publications

(49 citation statements)

References 66 publications

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“…This test-particle method has the disadvantage that the particles and fields do not evolve self-consistently. An alternative approach that has been more actively pursued in recent years is to track each source of plasma separately in its own fluid in a multi-fluid MHD model of the magnetosphere (e.g., Glocer et al, 2009Glocer et al, , 2018Glocer et al, , 2020Wiltberger et al, 2010;Winglee et al, 2002). While this methodology does not allow for non-Maxwellian distributions, it does allow for the self-consistent evolution of both plasma and electromagnetic fields.…”

Section: The Ionospheric Plasma Source From a Global Modeling Perspectivementioning

confidence: 99%

Impacts of Ionospheric Ions on Magnetic Reconnection and Earth's Magnetosphere Dynamics

Toledo‐Redondo

André

Aunai

et al. 2021

Reviews of Geophysics

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Ionospheric ions (mainly H + , He + , and O + ) escape from the ionosphere and populate the Earth's magnetosphere. Their thermal energies are usually low when they first escape the ionosphere, typically a few electron volt to tens of electron volt, but they are energized in their journey through the magnetosphere. The ionospheric population is variable, and it makes significant contributions to the magnetospheric mass density in key regions where magnetic reconnection is at work. Solar windmagnetosphere coupling occurs primarily via magnetic reconnection, a key plasma process that enables transfer of mass and energy into the near-Earth space environment. Reconnection leads to the triggering of magnetospheric storms, auroras, energetic particle precipitation and a host of other magnetospheric phenomena. Several works in the last decades have attempted to statistically quantify the amount of ionospheric plasma supplied to the magnetosphere, including the two key regions where magnetic reconnection occurs: the dayside magnetopause and the magnetotail. Recent in situ observations by the Magnetospheric Multiscale spacecraft and associated modeling have advanced our current understanding of how ionospheric ions alter the magnetic reconnection process, including its onset and efficiency. This article compiles the current understanding of the ionospheric plasma supply to the magnetosphere. It reviews both the quantification of these sources and their effects on the process of magnetic reconnection. It also provides a global description of how the ionospheric ion contribution modifies the way the solar wind couples to the Earth's magnetosphere and how these ions modify the global dynamics of the near-Earth space environment.Plain Language Summary Above the neutral atmosphere, space is filled with charged particles, which are tied to the Earth's magnetic field. The particles come from two sources, the solar wind and the Earth's upper atmosphere. Most of the solar wind particles are deflected by the Earth´s magnetic field, but some can penetrate into near-Earth space. The ionized layer of the upper atmosphere is continuously ejecting particles into space, which have low energies and are difficult to measure. We investigate the relative importance of the two charged particle sources for the dynamics of plasma processes in near-Earth space. In particular, we consider the effects of these sources in magnetic reconnection. Magnetic reconnection allows initially separated plasma regions to become magnetically connected and mix, and converts magnetic energy to kinetic energy of charged particles. Magnetic reconnection is the main driver of geomagnetic activity in the near-Earth space, and is responsible for the release of energy that drives a variety of space weather effects. We highlight the fact that plasma from the ionized upper atmosphere contributes a significant part of the density in the key regions where magnetic reconnection is at work, and that this contribution is larger when the geomagnetic activity is high. TOLEDO-RE...

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Section: The Ionospheric Plasma Source From a Global Modeling Perspectivementioning

confidence: 99%

Impacts of Ionospheric Ions on Magnetic Reconnection and Earth's Magnetosphere Dynamics

Toledo‐Redondo

André

Aunai

et al. 2021

Reviews of Geophysics

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“…While it might be possible to capture some of these features by imposing convection drifts and a tailward boundary condition on a SAMI2 simulation, a complete numerical description, including zonal convection drifts, are obtainable only via three-dimensional simulation. Ultimately, such modeling will need to be placed into the context of a global magnetosphere simulation, such as by Glocer et al (2020).…”

Section: Discussion: Bottom-up Refillingmentioning

confidence: 99%

Counterstreaming Cold H+, He+, O+, and N+ Outflows in the Plasmasphere

Krall

Huba

2021

Front. Astron. Space Sci.

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The Naval Research Laboratory (NRL) Sami3 is Also a Model of the Ionosphere (SAMI3) ionosphere/plasmasphere code is used to examine H+, He+, N+, and O+ thermal outflows during a storm. Here, H+ and He+ outflows are associated with refilling while O+ and N+ outflows are associated with ring current heating. An improved model of counterstreaming H+ outflows from the two hemispheres is presented, using an implementation of SAMI3 with two fluid species for H+. The two-fluid H+ model avoids nonphysical high-altitude “top-down refilling” density peaks seen in one-fluid H+ simulations. Counterstreaming cold ion populations are found in all cases. In these fully three-dimensional simulations with realistic magnetosphere boundary conditions, nonphysical top-down refilling density peaks were milder than those found in previous single-field-line or single-magnetic-longitude simulations. In the present two-fluid H+ case, “bottom-up refilling” density peaks were so mild as to be difficult to detect. For O+ and N+, the nonphysical high-altitude density peak is a brief (1–2 h) transient that occurs when heating-driven northward and southward flows first meet. In general, He+ outflows mimic H+ outflows while N+ outflows mimic O+ outflows.

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“…Several studies have investigated the role of ionospheric sources in populating the plasma sheet. Using test particle motion in global MHD simulation fields (e.g., Huddleston et al, 2005;Moore et al, 2005;Peroomian et al, 2007) or multi-fluid MHD codes (e.g., Glocer et al, 2020;Welling & Ridley, 2010), it was found that global convection was effective in transporting ions of ionospheric origin through the lobes into the PSBL and the plasma sheet, typically at large distances.…”

Section: Discussionmentioning

confidence: 99%

Acceleration of Oxygen Ions In Dipolarization Events: 2. PSBL Distributions

et al. 2021

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This paper represents the second part of an investigation of the acceleration of energetic oxygen ions from encounters with a dipolarization front (DF), based on test particle tracing in the fields of an MHD simulation. In this paper, we focus on distributions in the plasma sheet boundary layer (PSBL). O + beams close to the plasma sheet boundary are found to be less pronounced and/or delayed against the H + beams. The reason is that these particles are accelerated by nonadiabatic motion in the duskward electric field such that O + ions gain the same amount of energy, but only 1/4 of the speed of protons. This causes a delay and larger equatorward displacement by the E × B drift. In contrast, the O + beams somewhat deeper inside the plasma sheet, where previously multiple proton beams were found, are accelerated at an earthward propagating DF just like H + , forming a field-aligned beam at a similar speed as the lowest-energy H + beam. We found that the source location depends on the adiabaticity of the orbit. For larger adiabaticity, the beam ions originate initially from the outer plasma sheet, but later from the opposite PSBL or lobe, but for low adiabaticity, sources are well inside the plasma sheet. The energy gained from a single encounter of a DF is comparable to the kinetic energy associated with the front speed. Assuming maximum speeds of 500-1,000 km/s, this yields a mass dependent acceleration of about 1-5 keV for protons and 20-80 keV for oxygen ions, independent of their charge state. BIRN ET AL.

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A Case Study on the Origin of Near‐Earth Plasma

Cited by 37 publications

References 66 publications

Impacts of Ionospheric Ions on Magnetic Reconnection and Earth's Magnetosphere Dynamics

Impacts of Ionospheric Ions on Magnetic Reconnection and Earth's Magnetosphere Dynamics

Counterstreaming Cold H+, He+, O+, and N+ Outflows in the Plasmasphere

Acceleration of Oxygen Ions In Dipolarization Events: 2. PSBL Distributions

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