Ionospheric mass ejection in response to a CME

Moore, T. E.; Peterson, W. K.; Russell, C. T.; Chandler, M. O.; Collier, M. R.; Collin, H. L.; Craven, P. D.; Fitzenreiter, R. J.; Giles, B. L.; Pollock, C. J.

doi:10.1029/1999gl900456

Cited by 143 publications

(171 citation statements)

References 9 publications

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“…Because of their heavier mass, oxygen ions carry more energy per unit number density than protons. The enhanced ionospheric outflow during storms (e.g., Moore et al, 1999) enriches the O + content in the plasma sheet, and this stormtime variation is clearly seen in composition measurements (e.g., Young et al, 1982;Lennartsson and Shelley, 1986;Nose et al, 2001;Fu et al, 2001;Pulkkinen et al, 2001). However, these studies show substantial scatter about the mean trends.…”

Section: Ring Current Inputmentioning

confidence: 46%

Ring Current Energy Input and Decay

Kozyra

Liemohn

2003

Space Science Reviews

122

104

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Abstract.A new view of the ring current as an active element in the geospace system has emerged in which the ring current responds not only to changing convection electric fields imposed by solar wind interactions but to internal dynamics of the magnetosphere-ionosphere-atmosphere (geospace) system. Variations in the plasma sheet density, temperature and composition, saturation of the polar cap potential drop (and presumably the cross-tail potential drop), modifications to the imposed convection potential in the inner magnetosphere due to ring current shielding effects, the presence of a pre-existing ring current population, storm-substorm coupling, and strong convection with and without accompanying substorm activity all have an impact on the ring current strength, formation and loss. All of these internal processes imply that the geoeffectiveness of a solar wind driver cannot be predicted on the basis of the characteristics of the driver alone but must reflect key aspects of the dynamically changing geospace environment, itself. This review gives a summary of new information on ring current input and decay processes focusing on implications for the global geospace response to solar wind drivers during magnetic storms and on open questions that can be addressed with new ENA imaging techniques.

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Section: Ring Current Inputmentioning

confidence: 46%

Ring Current Energy Input and Decay

Kozyra

Liemohn

2003

Space Science Reviews

122

104

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“…That interpretation is also consistent with the locally enhanced O + flow density in the cusp regions of Figure 1, and it meshes quite well, in fact, with earlier reports on the outflow of O + ions with energies below 15 eV, since the rate of outflow of so-called ''suprathermal'' O + ions has been found to be especially strong in the cusp regions (''ion fountains'' [Lockwood et al, 1985]) and rather well correlated with the solar wind dynamic pressure, especially with its standard deviation, more so than with several other solar wind parameters [e.g., Moore et al, 1999;Elliott et al, 2001;Cully et al, 2003]. In terms of solar wind power input it might seem then that the kinetic energy flow density K ought to be especially important, a conjecture that can indeed be drawn from the comparison of K and S in Figures 4 and 5 as well.…”

Section: Discussionmentioning

confidence: 89%

“…[19] Since the peak upwelling, 10-eV type O + flux, on the dayside, is known to be better correlated with the preceding hourly standard deviation of a solar wind parameter, such as dynamic pressure (time shifted to Earth), than with the hourly mean parameter itself [Moore et al, 1999;Pollock et al, 1990]; it is probably preferable to compare our 12-and 24-s samplings with solar wind averages that are shorter than an hour. Using the $2-min Wind key parameters [Ogilvie et al, 1995;Lepping et al, 1995] individually, on the other hand, is most likely less than optimal, because the observed ion outflows at Polar may represent longer travel times than that from the source, ranging from a few seconds to several minutes at perigee, with low-energy O + ions being the slowest.…”

Section: Solar Wind Power Inputmentioning

confidence: 99%

Solar wind control of Earth's H⁺ and O⁺ outflow rates in the 15‐eV to 33‐keV energy range

2004

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[1] Earth's high-latitude outflow of H + and O + ions has been examined with the Toroidal Imaging Mass-Angle Spectrograph instrument on the Polar satellite in the 15-eV to 33-keV energy range over an almost 3-year period near solar minimum (1996)(1997)(1998). This outflow is compared with solar wind plasma and interplanetary magnetic field (IMF) data from the Wind spacecraft, the latter having been time shifted to the subsolar magnetopause and averaged for 15 min prior to each sampling of Earth's magnetic fieldaligned ion flow densities. When the flow data are arranged according to the polarity of the IMF B z (in GSM coordinates) and limited to times with B z > 3 nT or B z < À3 nT, the total rate of ion outflow is seen to be significantly enhanced with negative B z , typically by factors of 2.5-3 for the O + and 1.5-2 for the H + , more than previously reported from similar but less extensive comparisons. With either IMF B z polarity the rate of ion outflow is well correlated with the solar wind energy flow density, especially well with the density of kinetic energy flow. The rate of ion outflow within the instrument's energy range is a strong function of the Polar satellite altitude, increasing almost threefold from perigee (R $ 2 R E ) toward apogee (R $ 4-9 R E ) for O + ions, i.e., up to 10 26 ions s À1 or more per hemisphere. The apogee enhancement may be still larger for the H + , but it is obscured by mantle flow of cusp origin solar H + . Ion mean energy also increases with altitude, leading to about a twentyfold increase in the O + energy flow rate from Polar perigee to apogee altitude, reaching values of 20 GW or more per hemisphere. While the perigee outflow of H + has little or no seasonal modulation, in terms of ions s À1 the O + outflow rates at both altitudes do increase during local summer and so does the rate of cusp origin H + flow near apogee. The latter rate, in fact, has very similar seasonal modulation as the O + rates, suggesting that it has a significant influence on the O + outflow.

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“…[46] It has often been observed that powerful ionospheric escape events, referred to as ionospheric mass ejections [Moore et al, 1999], often contain appreciable amounts of the molecular ions N 2 + and NO + . Wilson and Craven [1999] showed that such events were associated with strong and prolonged (>15 min) convection of the ionosphere.…”

Section: Discussionmentioning

confidence: 99%

Mechanisms of ionospheric mass escape

Moore

Khazanov

2010

J. Geophys. Res.

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[1] The dependence of ionospheric O + escape flux on electromagnetic energy flux and electron precipitation into the ionosphere is derived for a hypothetical ambipolar pickup process, powered the relative motion of plasmas and neutral upper atmosphere, and by electron precipitation, at heights where the ions are magnetized but influenced by photoionization, collisions with gas atoms, ambipolar and centrifugal acceleration. Ion pickup by the convection electric field produces "ring-beam" or toroidal velocity distributions, as inferred from direct plasma measurements, from observations of the associated waves, and from the spectra of incoherent radar echoes. Ring beams are unstable to plasma wave growth, resulting in rapid relaxation via transverse velocity diffusion, into transversely accelerated ion populations. Ion escape is substantially facilitated by the ambipolar potential, but is only weakly affected by centrifugal acceleration. If, as cited simulations suggest, ion ring beams relax into nonthermal velocity distributions with characteristic speed equal to the local ion-neutral flow speed, a generalized "Jeans escape" calculation shows that the escape flux of ionospheric O + increases with Poynting flux and with precipitating electron density in rough agreement with observations.

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Ionospheric mass ejection in response to a CME

Abstract: Abstract. We report observations of a direct ionospheric plasma outflow response to the incidence of an interplanetary shock and associated coronal mass ejection (CME) upon

Cited by 143 publications

References 9 publications

Ring Current Energy Input and Decay

Ring Current Energy Input and Decay

Solar wind control of Earth's H⁺ and O⁺ outflow rates in the 15‐eV to 33‐keV energy range

Mechanisms of ionospheric mass escape

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Ionospheric mass ejection in response to a CME

Abstract: Abstract. We report observations of a direct ionospheric plasma outflow response to the incidence of an interplanetary shock and associated coronal mass ejection (CME) upon

Cited by 143 publications

References 9 publications

Ring Current Energy Input and Decay

Ring Current Energy Input and Decay

Solar wind control of Earth's H+ and O+ outflow rates in the 15‐eV to 33‐keV energy range

Mechanisms of ionospheric mass escape

Contact Info

Product

Resources

About

Solar wind control of Earth's H⁺ and O⁺ outflow rates in the 15‐eV to 33‐keV energy range