Testing electric field models using ring current ion energy spectra from the Equator-S ion composition (ESIC) instrument

Abstract. During the main and early recovery phase of a geomagnetic storm on February 18, 1998, the Equator-S ion composition instrument (ESIC) observed spectral features which typically represent the differences in loss along the drift path in the energy range (5–15 keV/e) where the drift changes from being E × B dominated to being gradient and curvature drift dominated. We compare the expected energy spectra modeled using a Volland-Stern electric field and a Weimer electric field, assuming charge exchange along the drift path, with the observed energy spectra for H+ and O+. We find that using the Weimer electric field gives much better agreement with the spectral features, and with the observed losses. Neither model, however, accurately predicts the energies of the observed minima.Key words. Magnetospheric physics (energetic particles trapped; plasma convection; storms and substorms)

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Statistical analysis of storm-time near-Earth current systems

Annales Geophysicae ◽

10.5194/angeo-33-965-2015 ◽

2015 ◽

Vol 33 (8) ◽

pp. 965-982 ◽

Cited By ~ 8

Author(s):

M. W. Liemohn ◽

R. M. Katus ◽

R. Ilie

Keyword(s):

Electric Field ◽

Ring Current ◽

Recovery Phase ◽

Hot Electron ◽

Early Recovery ◽

Superposed Epoch Analysis ◽

Tail Current ◽

Near Earth Space ◽

Epoch Analysis ◽

Current Systems

Abstract. Currents from the Hot Electron and Ion Drift Integrator (HEIDI) inner magnetospheric model results for all of the 90 intense storms (disturbance storm-time (Dst) minimum < −100 nT) from solar cycle 23 (1996–2005) are calculated, presented, and analyzed. We have categorized these currents into the various systems that exist in near-Earth space, specifically the eastward and westward symmetric ring current, the partial ring current, the banana current, and the tail current. The current results from each run set are combined by a normalized superposed epoch analysis technique that scales the timeline of each phase of each storm before summing the results. It is found that there is a systematic ordering to the current systems, with the asymmetric current systems peaking during storm main phase (tail current rising first, then the banana current, followed by the partial ring current) and the symmetric current systems peaking during the early recovery phase (westward and eastward symmetric ring current having simultaneous maxima). The median and mean peak amplitudes for the current systems ranged from 1 to 3 MA, depending on the setup configuration used in HEIDI, except for the eastward symmetric ring current, for which the mean never exceeded 0.3 MA for any HEIDI setup. The self-consistent electric field description in HEIDI yielded larger tail and banana currents than the Volland–Stern electric field, while the partial and symmetric ring currents had similar peak values between the two applied electric field models.

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Evolution of ring current ion energy spectra during the storm recovery phase: Implication for dominant ion loss processes

Journal of Geophysical Research Atmospheres ◽

10.1029/2010ja015628 ◽

2011 ◽

Vol 116 (A5) ◽

Cited By ~ 5

Author(s):

K. Keika ◽

P. C. Brandt ◽

M. Nosé ◽

D. G. Mitchell

Keyword(s):

Ring Current ◽

Recovery Phase ◽

Energy Spectra ◽

Ion Energy

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Predictive Metabolomics Evaluation of Nutrition-Modulated Metabolic Stress Responses in Human Blood Serum During the Early Recovery Phase of Strenuous Physical Exercise

Journal of Proteome Research ◽

10.1021/pr900081q ◽

2009 ◽

Vol 8 (6) ◽

pp. 2966-2977 ◽

Cited By ~ 79

Author(s):

Elin Chorell ◽

Thomas Moritz ◽

Stefan Branth ◽

Henrik Antti ◽

Michael B. Svensson

Keyword(s):

Physical Exercise ◽

Blood Serum ◽

Human Blood ◽

Stress Responses ◽

Metabolic Stress ◽

Recovery Phase ◽

Human Blood Serum ◽

Early Recovery ◽

Strenuous Physical Exercise ◽

Early Recovery Phase

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Life dissatisfaction in the pre-operative and early recovery phase predicts low functional ability and coping among post-operative patients with lumbar spinal stenosis: a 2-year prospective study

Disability and Rehabilitation ◽

10.3109/09638288.2010.503255 ◽

2010 ◽

Vol 33 (7) ◽

pp. 599-604 ◽

Cited By ~ 8

Author(s):

Sanna Sinikallio ◽

Heli Koivumaa-Honkanen ◽

Timo Aalto ◽

Olavi Airaksinen ◽

Soili M. Lehto ◽

...

Keyword(s):

Prospective Study ◽

Spinal Stenosis ◽

Lumbar Spinal Stenosis ◽

Functional Ability ◽

Recovery Phase ◽

Early Recovery ◽

Life Dissatisfaction ◽

Lumbar Spinal ◽

And Coping ◽

Early Recovery Phase

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IMF effect on the polar cap contraction and expansion during a period of substorms

Annales Geophysicae ◽

10.5194/angeo-31-1021-2013 ◽

2013 ◽

Vol 31 (6) ◽

pp. 1021-1034 ◽

Cited By ~ 4

Author(s):

A. T. Aikio ◽

T. Pitkänen ◽

I. Honkonen ◽

M. Palmroth ◽

O. Amm

Keyword(s):

Recovery Phase ◽

Bow Shock ◽

Polar Cap ◽

Reconnection Rate ◽

Early Recovery ◽

Mhd Simulation ◽

Expansion Phase ◽

Contraction And Expansion ◽

Good Agreement ◽

The Imf

Abstract. The polar cap boundary (PCB) location and motion in the nightside ionosphere has been studied by using measurements from the EISCAT radars and the MIRACLE magnetometers during a period of four substorms on 18 February 2004. The OMNI database has been used for observations of the solar wind and the Geotail satellite for magnetospheric measurements. In addition, the event was modelled by the GUMICS-4 MHD simulation. The simulation of the PCB location was in a rather good agreement with the experimental estimates at the EISCAT longitude. During the first three substorm expansion phases, neither the local observations nor the global simulation showed any poleward motions of the PCB, even though the electrojets intensified. Rapid poleward motions of the PCB took place only in the early recovery phases of the substorms. Hence, in these cases the nightside reconnection rate was locally higher in the recovery phase than in the expansion phase. In addition, we suggest that the IMF Bz component correlated with the nightside tail inclination angle and the PCB location with about a 17-min delay from the bow shock. By taking the delay into account, the IMF northward turnings were associated with dipolarizations of the magnetotail and poleward motions of the PCB in the recovery phase. The mechanism behind this effect should be studied further.

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Electron flux enhancement in the inner radiation belt during moderate magnetic storms

Annales Geophysicae ◽

10.5194/angeo-25-1359-2007 ◽

2007 ◽

Vol 25 (6) ◽

pp. 1359-1364 ◽

Cited By ~ 10

Author(s):

H. Tadokoro ◽

F. Tsuchiya ◽

Y. Miyoshi ◽

H. Misawa ◽

A. Morioka ◽

...

Keyword(s):

Radiation Belt ◽

Electron Flux ◽

Recovery Phase ◽

Magnetic Activity ◽

Magnetic Storms ◽

Natural Phenomena ◽

Early Recovery ◽

Flux Enhancement ◽

Angle Scattering ◽

Order Of Magnitude

Abstract. During moderate magnetic storms, an electron channel (300–1100 keV) of the NOAA satellite has shown sudden electron flux enhancements in the inner radiation belt. After examinating the possibility of contamination by different energetic particles, we conclude that these electron flux enhancements are reliable enough to be considered as natural phenomena, at least for the cases of small to moderate magnetic storms. Here, we define small and moderate storms to be those in which the minimum Dst ranges between −30 and −100 nT. The electron flux enhancements appear with over one order of magnitude at L~2 during these storms. The enhancement is not accompanied by any transport of electron flux from the outer belt. Statistical analysis shows that these phenomena have a duration of approximately 1 day during the period, starting with the main phase to the early recovery phase of the storms. The flux enhancement shows a dawn-dusk asymmetry; the amount of increased flux is larger in the dusk side. We suggest that this phenomenon could not be caused by the radial diffusion but would be due to pitch-angle scattering at the magnetic equator. The inner belt is not in a stationary state, as was previously believed, but is variable in response to the magnetic activity.

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Secondary ion energy spectra of polycrystalline transition metals and aluminium

International Journal of Mass Spectrometry and Ion Physics ◽

10.1016/0020-7381(78)80089-8 ◽

1978 ◽

Vol 28 (3) ◽

pp. 233-256 ◽

Cited By ~ 15

Author(s):

K.J. Snowdon ◽

R.J. MacDonald

Keyword(s):

Transition Metals ◽

Energy Spectra ◽

Ion Energy ◽

Secondary Ion

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A multi-satellite study of accelerated ionospheric ion beams above the polar cap

Annales Geophysicae ◽

10.5194/angeo-24-1665-2006 ◽

2006 ◽

Vol 24 (6) ◽

pp. 1665-1684 ◽

Cited By ~ 20

Author(s):

R. Maggiolo ◽

J. A. Sauvaud ◽

D. Fontaine ◽

A. Teste ◽

E. Grigorenko ◽

...

Keyword(s):

Electric Field ◽

Potential Drop ◽

Auroral Zone ◽

Ion Beams ◽

Distribution Functions ◽

Convection Velocity ◽

Polar Cap ◽

Ion Energy ◽

Polar Cusp ◽

Oxygen Ions

Abstract. This paper presents a study of nearly field-aligned outflowing ion beams observed on the Cluster satellites over the polar cap. Data are taken at geocentric radial distances of the order of 5–9 RE. The distinction is made between ion beams originating from the polar cusp/cleft and beams accelerated almost along the magnetic field line passing by the spacecraft. Polar cusp beams are characterized by nearly field-aligned proton and oxygen ions with an energy ratio EO+ / EH+, of the order of 3 to 4, due to the ion energy repartition inside the source and to the latitudinal extension of the source. Rapid variations in the outflowing ion energy are linked with pulses/modifications of the convection electric field. Cluster data allow one to show that these perturbations of the convection velocity and the associated ion structures propagate at the convection velocity. In contrast, polar cap local ion beams are characterized by field-aligned proton and oxygen ions with similar energies. These beams show the typical inverted V structures usually observed in the auroral zone and are associated with a quasi-static converging electric field indicative of a field-aligned electric field. The field-aligned potential drop fits well the ion energy profile. The simultaneous observation of precipitating electrons and upflowing ions of similar energies at the Cluster orbit indicates that the spacecraft are crossing the mid-altitude part of the acceleration region. In the polar cap, the parallel electric field can thus extend to altitudes higher than 5 Earth radii. A detailed analysis of the distribution functions shows that the ions are heated during their parallel acceleration and that energy is exchanged between H+ and O+. Furthermore, intense electrostatic waves are observed simultaneously. These observations could be due to an ion-ion two-stream instability.

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