Unusually high thermospheric hydrogen density prior to severe storm of September 8, 2017 and its impact on the storm manifestations

Atomic hydrogen plays a key role for the plasmasphere, exosphere, and the nighttime ionosphere. It directly impacts the rate of plasmasphere refilling after strong magnetic storms as atomic hydrogen is the primary source of hydrogen ions. It is the source of the geocorona, which significantly affects ring current decay during the recovery phase of magnetic storms.Our previous studies with the Kharkiv incoherent scatter radar (49.6 N, 36.3&#160;E), Arase and DMSP satellite missions, and FLIP physical model showed that during magnetically quiet periods of 2016&#8211;2018 the hydrogen density was generally a factor of 2 higher than from the NRLMSIS00-E model (Kotov et al., 2018).Even larger values of thermospheric hydrogen density were detected prior to the severe storm of September 8, 2017. With Kharkiv IS radar, AWDANet whistler receivers, Arase satellite, and TEC data we found that during the nights of September 5 to 6 and September 6 to 7, the thermospheric hydrogen density had to be at least a factor of 4 higher than the values from NRLMSIS00-E model i.e. ~100% higher than expected from our previous studies. We discuss the possible mechanisms that could lead to the increased hydrogen density.Such high hydrogen densities may be the reason for very quick recovery of inner plasmasphere after the severe depletion by the storm of September 8, 2017 (Obana et al., 2019).References:1. Kotov, D. V., Richards, P. G., Truhl&#237;k, V., Bogomaz, O. V., Shulha, M. O., Maruyama, N., et al. ( 2018). Coincident observations by the Kharkiv IS radar and ionosonde, DMSP and Arase (ERG) satellites, and FLIP model simulations: Implications for the NRLMSISE&#8208;00 hydrogen density, plasmasphere, and ionosphere. Geophysical Research Letters, 45, 8062&#8211; 8071. https://doi.org/10.1029/2018GL0792062. Obana, Y., Maruyama, N., Shinbori, A., Hashimoto, K. K., Fedrizzi, M., Nos&#233;, M., et al. (2019). Response of the ionosphere&#8208;plasmasphere coupling to the September 2017 storm: What erodes the plasmasphere so severely? Space Weather, 17, 861&#8211;876. https://doi.org/10.1029/2019SW002168

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A two-step ring current decay time model during the passive recovery phase of magnetic storms

Journal of Atmospheric and Solar-Terrestrial Physics ◽

10.1016/j.jastp.2011.04.007 ◽

2011 ◽

Vol 73 (13) ◽

pp. 1831-1839 ◽

Cited By ~ 1

Author(s):

R. Monreal MacMahon ◽

C. Llop-Romero

Keyword(s):

Decay Time ◽

Ring Current ◽

Recovery Phase ◽

Magnetic Storms ◽

Time Model ◽

Passive Recovery ◽

Current Decay

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Atomic hydrogen density measurements in an ion source plasma using a VUV absorption spectrometer

Review of Scientific Instruments ◽

10.1063/1.1139693 ◽

1988 ◽

Vol 59 (8) ◽

pp. 1479-1481 ◽

Cited By ~ 14

Author(s):

G. C. Stutzin ◽

A. T. Young ◽

A. S. Schlachter ◽

J. W. Stearns ◽

K. N. Leung ◽

...

Keyword(s):

Atomic Hydrogen ◽

Ion Source ◽

Density Measurements ◽

Hydrogen Density ◽

Absorption Spectrometer

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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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Ring current decay rates of magnetic storms: A statistical study from 1957 to 1998

Journal of Geophysical Research Atmospheres ◽

10.1029/2000ja000430 ◽

2002 ◽

Vol 107 (A5) ◽

Cited By ~ 27

Author(s):

Sergio Dasso

Keyword(s):

Ring Current ◽

Statistical Study ◽

Magnetic Storms ◽

Decay Rates ◽

Current Decay

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Another way of deriving the ring current decay time during disturbed periods

Annals of Geophysics ◽

10.4401/ag-4115 ◽

1995 ◽

Vol 38 (2) ◽

Author(s):

M. M. Zossi de Artigas ◽

J. R. Manzano

Keyword(s):

Ring Current ◽

Coupling Parameter ◽

Life Time ◽

Recovery Phase ◽

Main Phase ◽

Physical Analysis ◽

Inner Magnetosphere ◽

Current Decay ◽

The Many ◽

Energy Dissipated

Coupling parameter, E, and the total energy dissipated by the magnetosphere, UT, are determined for six disturbed periods, following three known criteria for UT computation. It is observed that UT exceeds E for Dst < -90 nT, for alI models. Differences between models reside on the estimated valnes for the particles' life time il1 the equatorial ring current. The values of TR, used in the models, are small during the main phase of the di."turbance, in disagreement with the charge exchange life time of the majority species, H+ and O'-. Based on this conclusion, a different criterion to calculate TR is proposed, differentiating the different stages of the perturbation. TR is calculated, for the main phase of the storm, from the rate of energy deposition estimation, Q, in the ring current. For Dst recovery phase, the vallles are obtained from a ring current decay law computation. The UTvu calculated, physically more coherent with the processes occurring during the event, is now smaller than expected. In this sense, it is understood that the power generated by the solar wind-magnetosphere dy- namo, should also be distributed in the inner magnetosphere, auroral zones and equatorial ring current, as in the outer magnetosphere, plasmoids in the tail shot in antisolar direction. A further adjustment of E, with the Chapman-Ferraro distance, 10' variable, has been made. Although the reslllts, improve the estimation of E, they are sti!l smaller than UT, except UTNU, for some disturbed periods. This result indicates the uncertainty in the computation of the input energy, by using the many expressions proposed in the literature, which are always presented as laws proportional to a given group of parameters, with an unknown factor of proportionality, which deserves more detailed physical analysis.

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A High-Velocity Component of Atomic Hydrogen in Comet Bennett (1970 II)

International Astronomical Union Colloquium ◽

10.1017/s0252921100500979 ◽

1976 ◽

Vol 25 (Part1) ◽

pp. 316-321

Author(s):

H. U. Keller ◽

Gary E. Thomas

Keyword(s):

Radiation Pressure ◽

Velocity Component ◽

Atomic Hydrogen ◽

Orbital Plane ◽

Field Of View ◽

Lyman Alpha ◽

Hydrogen Density ◽

University Of Colorado ◽

Alpha Emission ◽

The University

The Lyman alpha emission from Comet Bennett (1970II) was measured near perihelion (March 1970) by the University of Colorado ultraviolet photometer experiment on OGO-5 The spectrometer field of view of about 3° crossed the cometary hydrogen coma four times. The hydrogen coma was observed to extend more than 30 x 106 km in the antisolar direction.A model for the hydrogen density was developed which took the actual cometary motion and the gradients of the forces of gravitation and radiation pressure into account Exact trajectories of atoms in the orbital plane representing the column densities perpendicular to the plane were calculated. The variation of the hydrogen lifetime along the trajectory as well as the solar Lα profile were considered.

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Absolute atomic hydrogen density measurements in an atmospheric pressure plasma jet: generation, transport and recombination from the active discharge region to the effluent

Plasma Sources Science and Technology ◽

10.1088/1361-6595/ab7853 ◽

2020 ◽

Vol 29 (4) ◽

pp. 04LT01 ◽

Cited By ~ 3

Author(s):

Y Yue ◽

V S S K Kondeti ◽

P J Bruggeman

Keyword(s):

Atmospheric Pressure ◽

Atomic Hydrogen ◽

Atmospheric Pressure Plasma ◽

Plasma Jet ◽

Atmospheric Pressure Plasma Jet ◽

Discharge Region ◽

Density Measurements ◽

Hydrogen Density ◽

Pressure Plasma

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The relativistic electron response in the outer radiation belt during magnetic storms

Annales Geophysicae ◽

10.5194/angeo-20-957-2002 ◽

2002 ◽

Vol 20 (7) ◽

pp. 957-965 ◽

Cited By ~ 55

Author(s):

R. H. A. Iles ◽

A. N. Fazakerley ◽

A. D. Johnstone ◽

N. P. Meredith ◽

P. Bühler

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Wind Speed ◽

Interplanetary Magnetic Field ◽

Relativistic Electron ◽

Radiation Belt ◽

Solar Wind Speed ◽

Recovery Phase ◽

Magnetic Storms ◽

Outer Radiation Belt

Abstract. The relativistic electron response in the outer radiation belt during magnetic storms has been studied in relation to solar wind and geomagnetic parameters during the first six months of 1995, a period in which there were a number of recurrent fast solar wind streams. The relativistic electron population was measured by instruments on board the two microsatellites, STRV-1a and STRV-1b, which traversed the radiation belt four times per day from L ~ 1 out to L ~ 7 on highly elliptical, near-equatorial orbits. Variations in the E > 750 keV and E > 1 MeV electrons during the main phase and recovery phase of 17 magnetic storms have been compared with the solar wind speed, interplanetary magnetic field z-component, Bz , the solar wind dynamic pressure and Dst *. Three different types of electron responses are identified, with outcomes that strongly depend on the solar wind speed and interplanetary magnetic field orientation during the magnetic storm recovery phase. Observations also confirm that the L-shell, at which the peak enhancement in the electron count rate occurs has a dependence on Dst *.Key words. Magnetospheric physics (energetic particles, trapped; storms and substorms) – Space plasma physics (charged particle motion and accelerations)

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