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An example of velocity space distributions of O + ions measured on 31 October 2001, 19 March 2001 and 19 November 2001. These distributions are shown according to the spacecraft's coordinate system and the velocity space is defined in terms of velocities parallel (V par ) and perpendicular (V perp ) to the magnetic field direction. The scales are ±50 km s −1. The beams were also observed by SC3 and 4.
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Numerous observations have shown that ions flow out of the ionosphere
during substorms with more fluxes leaving as the substorm intensity increases
(Wilson et al., 2004). In this article we show observations of low-energy (few
tens of electron volts) ionospheric ions flowing out periods without substorms,
determined using the Wideband Imaging Camer...
Context in source publication
Context 1
... function: Figure 5 shows examples of the velocity space distributions of O + observed for the three days discussed above. Ion beams are observed by all three Cluster spacecraft (SC1, 3, and 4) but we only show data from Clus- ter 1. These are 2-D cuts of the 3-D distributions presented in the spacecraft frame where the coordinates are relative to di- rections parallel (V par ) and perpendicular (V perp ) to the mag- netic field. The scales of the x and y axes are ±50 km s −1 . On these three days, Cluster was traversing the Southern Hemi- sphere, and the positive V par corresponds to ions flowing par- allel to the magnetic field direction out of the ionosphere. All of the ions are field-aligned beams occupying a very small re- gion of the velocity space (one or two pitch-angle bins clos- est to the direction of B), and the measured O + beams have a velocity of ∼ 20 km s −1 (for spacecraft potential correction, see ...
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Citations
... We now study the dispersion relation using parameters typically observed in Earth's magnetosphere, specially in the auroral acceleration region, at around 2 R e : B 0 = 0.043 G; n i0 = 10 2 cm −3 ; T i = T e = 1 eV (Kletzing, Mozer & Torbert 1998 ;Shri v astav a & Tiwari 2004 ). Follo wing satellite observ ations in the auroral zone (Chaston et al. 2005 ;Parks et al. 2015 ), we assume that the ion population is formed by H + , He + , and O + with number densities of, respectively, n H + = 0 . 9 n i0 , n He + = 0 . ...
Dust populations in space plasmas are often described by a size distribution function, generally a power law distribution. In view of that, we include this feature in the kinetic description of a homogeneous magnetized dusty plasma with electrically charged immobile dust grains, in order to study its effects in the propagation and damping of Alfvén waves. The dispersion relation is numerically solved using parameters typically found in the dust-driven stellar winds of carbon-rich stars and in Earth’s auroral acceleration region, two space systems with unalike plasma parameters and in which Alfvén waves are known to play important roles in the plasma acceleration and heating processes. We show that the characteristics of the normal modes, namely the ion cyclotron and whistler modes, will change when one considers a power law distribution of dust sizes in the theory, as compared to a mono-sized dust population; and that these differences will depend on the exponent p of the power law, which alters the plasma charge imbalance between electrons and ions. We also notice that power-law distribution functions will modify the waves’ damping rate values. In particular, we show that in a stellar wind environment the ion cyclotron mode at very small wavenumber decreases with the reduction of p, while for higher wavenumber the damping of this mode increases with the reduction of p. For the Earth’s magnetosphere, the results obtained show that the wave damping increases with the decrease of p for all wavenumbers, for the parameters considered in the analysis.
... Physically, this can be interpreted as the result of high to low latitude coupling mechanisms acting during quiet periods, thus pointing towards a possible co-variability of the different current systems within the near-Earth electromagnetic environment as a result of a closure of the electric circuit [48]. This seems to point also towards recent findings of low energy (few tens of electron volts) field aligned ionospheric ions flowing out during quiet periods, being a major source of heavy ions for the plasma sheet and lobe [49]. Conversely, the observation that the coupling is stronger during the initial phase (development) of a geomagnetic storm (with the injection of ionospheric oxygen ions into the outer edge of the magnetospheric ring current) points toward a net transfer of variability from the high latitude ionosphere to the low latitude magnetosphere [17,19,21]. ...
An accurate understanding of dissimilarities in geomagnetic variability between quiet and disturbed periods has the potential to vastly improve space weather diagnosis. In this work, we exploit some recently developed methods of dynamical system theory to provide new insights and conceptual ideas in space weather science. In particular, we study the co-variation and recurrence statistics of two geomagnetic indices, SYM-H and AL, that measure the intensity of the globally symmetric component of the equatorial electrojet and that of the westward auroral electrojet, respectively. We find that the number of active degrees of freedom, required to describe the phase space dynamics of both indices, depends on the geomagnetic activity level. When the magnetospheric substorm activity, as monitored by the AL index, increases, the active number of degrees of freedom increases at high latitudes above the dimension obtained through classical time delay embedding methods. Conversely, a reduced number of degrees of freedom is observed during geomagnetic storms at low latitude by analysing the SYM-H index. By investigating time-dependent relations between both indices we find that a significant amount of information is shared between high and low latitude current systems originating from coupling mechanisms within the magnetosphere–ionosphere system as the result of a complex interplay between processes and phenomena of internal origin activated by the triggering of external source processes. Our observations support the idea that the near-Earth electromagnetic environment is a complex system far from an equilibrium.
... Energetic heavy ion outflow, originating from the auroral oval, has usually been associated with high-activity periods (Daglis et al., 1990;Wilson et al., 2004). In order to examine whether the substorms are the only cause of ions flowing out of the auroral oval, Parks et al. (2015) analyzed H + , He + , and O + ion flow data obtained in 2001-2002 by the CIS instrument at altitudes between ∼2 R E and ∼10 R E . To identify periods with or without substorms, auroral images from the Wideband Imaging Camera (WIC) on the IMAGE spacecraft (Mende et al., 2000), together with the AE index, were then used. ...
Cluster was the first mission in the terrestrial magnetosphere to involve four spacecraft in a tetrahedral configuration, providing three‐dimensional measurements of the space plasma parameters. Cluster was also equipped with a very comprehensive instrumentation, allowing the measurement of the ion populations outflowing from the ionosphere, their circulation in the magnetosphere, and their eventual escape to outer space. The observations of the outflowing and escaping ion populations performed by Cluster are reviewed and the most prominent results highlighted. These show the dominance in the magnetotail lobes of cold plasma outflows originating from the polar caps. For the energetic heavy ion outflow, the cusps constitute the main source. Their transport and acceleration through the polar cap into the lobes and then into the plasma sheet has been characterized. The dependence of the polar outflow on the solar wind parameters and on the geomagnetic activity has been evaluated for both cold ion populations and heavy energetic ions. For the latter, outflow has been observed during all periods but an increase by two orders of magnitude has been shown during extreme space weather conditions. This outflow is adequate to change the composition of the atmosphere over geological timescales. At lower latitudes, the existence of a plasmaspheric wind, providing a continuous leak from the plasmasphere, has been demonstrated. The general scheme of the outflowing ion circulation in the magnetosphere or escape, and its dependence on the IMF conditions, has been outlined. However, several questions remain open, waiting for a future space mission to address them.
... They have been also supplying key information on plasma sources and losses (e.g. Engwall et al. 2009;Dandouras 2013;Parks et al. 2015;Nagai et al. 2016;Slapak et al. 2017;Xu et al. 2019). However, the moderate mass resolution of their instrumentation (m/ m ≈ 5-7 for CODIF onboard Cluster (Rème et al. 2001) and m/ m ≈ 4 for HPCA on board MMS (Young et al. 2016)) does not allow distinguishing nitrogen from oxygen ions or any isotope ratios. ...
In this chapter, we review the contribution of space missions to the determination of the elemental and isotopic composition of Earth, Moon and the terrestrial planets, with special emphasis on currently planned and future missions. We show how these missions are going to significantly contribute to, or sometimes revolutionise, our understanding of planetary evolution, from formation to the possible emergence of life. We start with the Earth, which is a unique habitable body with actual life, and that is strongly related to its atmosphere. The new wave of missions to the Moon is then reviewed, which are going to study its formation history, the structure and dynamics of its tenuous exosphere and the interaction of the Moon’s surface and exosphere with the different sources of plasma and radiation of its environment, including the solar wind and the escaping Earth’s upper atmosphere. Missions to study the noble gas atmospheres of the terrestrial planets, Venus and Mars, are then examined. These missions are expected to trace the evolutionary paths of these two noble gas atmospheres, with a special emphasis on understanding the effect of atmospheric escape on the fate of water. Future missions to these planets will be key to help us establishing a comparative view of the evolution of climates and habitability at Earth, Venus and Mars, one of the most important and challenging open questions of planetary science. Finally, as the detection and characterisation of exoplanets is currently revolutionising the scope of planetary science, we review the missions aiming to characterise the internal structure and the atmospheres of these exoplanets.
... They have been also supplying key information on plasma sources and losses (e.g. Engwall et al. 2009;Dandouras 2013;Parks et al. 2015;Nagai et al. 2016;Slapak et al. 2017;Xu et al. 2019). However, the moderate mass resolution of their instrumentation (m/ m ≈ 5-7 for CODIF onboard Cluster (Rème et al. 2001) and m/ m ≈ 4 for HPCA on board MMS (Young et al. 2016)) does not allow distinguishing nitrogen from oxygen ions or any isotope ratios. ...
... The ions of ionospheric origin flow out into the Earth's magnetosphere as the polar wind, upwelling from the cusp, polar cap and ion beams which are accelerated in the auroral zone by the parallel electric fields. These escaping ions have been observed by observations from radars on the ground and also by numerous satellites (Parks et al. 2015). Electron acceleration along the magnetic field is a key process for aurora generation. ...
... Olsen and Chappell (1986) have reported the evidence of H + , He + and O + ions in the night side auroral region based on thermal ion measurements from the Retarding Ion Mass Spectrometer (RIMS) on Dynamics Explorer 1 (DE 1). The observations from other satellites confirming the existence of H + , He + and O + ions include Interball Auroral Probe (IAP) (Dubouloz et al. 1998), FAST (Chaston et al. 2003a, 2003b and Cluster (Chaston et al. 2005;Parks et al. 2015). The average ion mass of H + is 1, He + is 4 and O + is 16. ...
... Watt et al. (2005) developed a kinetic simulation code assuming Maxwellian plasma for studying the electron response to the propagating IAW pulses in auroral region. These waves have been rigorously investigated considering Maxwellian distribution function of electrons and ions in AAR as well as laboratory plasma (Thompson and Lysak 1996;Chaston et al. 2002;Dubinin et al. 2005;Watt et al. 2006;Rankin 2007, 2008;Parks et al. 2015). Agarwal et al. (2011Agarwal et al. ( , 2014 have investigated frequency and damping rate of IAW in cusp and plasma sheet boundary layer region considering finite ion gyroradius effect. ...
The propagation of inertial Alfvén wave is investigated in cold, low-, homogeneous and bi-Maxwellian plasma consisting of multi-ions (H⁺, He⁺ and O⁺). Kinetic approach is adopted to derive the dispersion relation, damping rate, group velocity and growth/ damping length of the wave. Figures are exhibited with respect to . Effects of density variation with multi-ions are analysed on frequency, damping rate, parallel and perpendicular components of group velocity and growth/ damping length of the inertial Alfvén wave. It is found that varying densities of multi-ions significantly influence the frequency, damping rate and group velocity of inertial Alfvén wave. The wave frequency is observed between 0.5 to 18~\mbox{s}^{- 1} pertaining to observational data. The increasing density of heavy ions reduces the frequency of waves. The presence of He⁺ and O⁺ enhances the damping of wave showing more transfer of energy from wave to particles leading to increase in electron acceleration. The order of parallel and perpendicular group velocity is found to be 10^{9}~\mbox{cm}/\mbox{s} and 10^{5}~\mbox{cm}/\mbox{s} respectively. Maximum perpendicular growth length is observed corresponding to the minimum damping rate of wave at , signifying the dynamics in transverse direction to the magnetic field which are more significant in the present analysis. The parameters relevant to auroral acceleration region are used for graphical analysis. The applications of present study may be towards the electron acceleration in the dynamics of auroral acceleration region consisting of heavy ions in background plasma.
... It is reviewed that many studies have reported observations emphasizing density variation of H + , He + and O + ions in PSBL region (Eastman et al. 1984(Eastman et al. , 1985Chapell et al. 1987;Bosqued et al. 2009;Denton et al. 2010;Du et al. 2011;Parks et al. 2015). A series of research work has been carried in the recent past to investigate the KAWs in plasma with heavy ions Wu 2005, 2011;Wu andYang 2006, 2007;Yang et al. 2014). ...
Kinetic Alfvén waves (KAWs) are investigated considering existence of multi-ions (H⁺, He⁺ and O⁺) in plasma sheet boundary layer (PSBL) region. The dispersion relation and damping rate of wave are derived by kinetic approach. The loss-cone index (for J=1 and ) and densities of multi-ions are varied to study the frequency and damping rate of wave over wide range of (where is perpendicular wave vector and is Larmor radius of H⁺ ion). The presence of multi-ions in plasma is assumed for four cases: (a) H⁺ only, (b) H⁺ and He⁺, (c) H⁺ and O⁺, (d) H⁺, He⁺ and O⁺ ions. The results of the cases (b), (c) and (d) are compared with (a) to understand the effects of He⁺ and O⁺ ions on KAW. It is observed that the frequency of the wave lies in range 0.1–4 Hz for each case. He⁺ enhances wave frequency with increase in steepness of loss-cone indices. O⁺ is more effective in Maxwellian plasma resulting maximum frequency for J=0. Increasing densities of He⁺ and O⁺ result in reduction of wave frequency at and enhancement in frequency at higher . Presence of He⁺ and O⁺ induce fluctuations in wave frequency. Reduction in damping rate due to He⁺ and O⁺ ions in loss-cone distribution signifies propagation of wave over long distances from PSBL towards auroral ionosphere. The parameters relevant to PSBL region are used in calculation of theoretical results. The results predict that the multi-ions possessing loss-cone distribution with varying densities significantly affect nature of KAW propagation.
... On average, O + dominates the global outflow of heavier ions. Estimates range from less than 10 25 to more than 10 26 ions s −1 , higher at higher geomagnetic activity and for more intense solar EUV radiation (Yau et al 1988, Cully et al 2003, Peterson et al 2006, Parks et al 2015. An order of magnitude estimate of the average over a solar cycle is a few times 10 25 ions s −1 . ...
This is a review of the mass balance of planet Earth, intended also for scientists not usually working with space physics or geophysics. The discussion includes both outflow of ions and neutrals from the ionosphere and upper atmosphere, and the inflow of meteoroids and larger objects. The focus is on ions with energies less than tens of eV originating from the ionosphere. Positive low-energy ions are complicated to detect onboard sunlit spacecraft at higher altitudes, which often become positively charged to several tens of volts. We have invented a technique to observe low-energy ions based on the detection of the wake behind a charged spacecraft in a supersonic ion flow. We find that low-energy ions usually dominate the ion density and the outward flux in large volumes in the magnetosphere. The global outflow is of the order of 1026 ions s-1. This is a significant fraction of the total number outflow of particles from Earth, and changes plasma processes in near-Earth space. We compare order of magnitude estimates of the mass outflow and inflow for planet Earth and find that they are similar, at around 1 kg s-1 (30 000 ton yr-1). We briefly discuss atmospheric and ionospheric outflow from other planets and the connection to evolution of extraterrestrial life.
... These beams include the polar wind, upwelling ions from the cusps and polar caps, and ion beams accelerated in the aurora by electric field parallel to the magnetic field direction. These ions are a significant plasma source for the lobes and the plasma sheet regions in the geomagnetic tail (Parks et al. (2015) and references therein). A recent investigation of the behavior of ion beams in inverted-V structures consisting of H + , He + , and O + showed that the ions are heated while accelerated along the magnetic field direction (Cui et al., 2014). ...
The ion composition experiment on Cluster measures 3-D distributions in one spin of the spacecraft (4 s). These distributions often measure field-aligned ion beams (H+, He+ and O+) accelerated out of the ionosphere. The standard model of these beams relies on a quasi-static U-shaped potential model. The beams contain important information about the structure and distribution of the U-shaped potential structures. For example, a simple beam with a narrow velocity range tells us that the particles are accelerated going through a quasi-static U-shaped potential structure localized in space. A more complex beam with a large range of velocities varying smoothly (a few tens of kilometers per second to > 100 km s−1) tells us that the potential structure is extended and distributed along the magnetic field. The Cluster experiment has now revealed new features about the beams. Some beams are broken into many individual structures each with their own velocity. The U-shaped potential model would interpret the new features in terms of particles accelerated by narrow isolated potential structures maintained over an extended region of the magnetic field. Another interpretation is that these features arise as Cluster traverses toward the center of a small-scale U-shaped potential region detecting particles accelerated on different equipotential contours. The estimate of the distance of the adjacent contours is ~ 590–610 m at a Cluster height of ~ 3.5 RE. The observed dimensions map to ~ 295–305 m in the ionosphere, suggesting Cluster has measured the potential structure of an auroral arc.
The acceleration and transport of high‐latitude ionospheric ion outflows, both bulk ion flows and suprathermal ion outflows, play a fundamental role in magnetosphere–ionosphere coupling. Bulk ion flows consist mainly of the polar wind and auroral bulk upflows (with flow energies up to a few eV) in the topside polar ionosphere, which are the primary sources of low‐energy H+ and O+ ions, respectively, for various ion acceleration processes at higher altitudes. These processes include perpendicular and parallel acceleration in the mid (~1000–5000 km) or high‐altitude auroral zone, which produce suprathermal (~10 eV to ~10 keV) ion outflows such as transversely accelerated ions, ion conics, and ion beams; and centrifugal acceleration in regions of curved or changing magnetic field at high altitudes (above ~3–4 RE). A significant fraction of ion outflows remains cold in the magnetosphere, where their transport is strongly influenced by the interplanetary magnetic field (IMF) and the prevailing convection electric field. This results in a preferential feeding of the dusk plasma sheet under duskward IMF, and a stronger transport to the plasma sheet compared to the magnetotail at times of strong convection.
