Response of the topside ionosphere over Arecibo to a moderate geomagnetic storm

Garzón, Diana Prado; Brum, C. G. M.; Echer, E.; Aponte, N.; Sulzer, M. P.; González, S. A.; Kerr, Robert B.; Waldrop, L.

doi:10.1016/j.jastp.2011.02.016

Cited by 14 publications

(21 citation statements)

References 23 publications

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“…This reaction mainly controls the production and loss of H + in the topside ionosphere [ Garzon et al ., ]. During our observation, [O + ] was much larger than [H + ] most of the time.…”

Section: The Topside Ionosphere Responsementioning

confidence: 59%

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The F region and topside ionosphere response to a strong geomagnetic storm at Arecibo

et al. 2013

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[1] We analyze the data derived from the Arecibo incoherent scatter radar measurements to investigate the response of the F region and topside ionosphere to a strong geomagnetic storm that occurred during the period of 5-6 August 2011. The meridional wind was extremely enhanced at the early stage of the storm. The peak velocity reached approximately 300 m/s at an altitude of 340 km, which is seldom seen at the Arecibo latitude. During the storm, the vertical ion drift caused by the meridional wind was positively correlated with that caused by the electric field, which is opposite to the quiet time relationship. The disturbed vertical ion drifts resulted in large ionospheric perturbations in the F and topside regions. Several collapses were observed in h m F 2 during the storm night. N m F 2 rapidly increased after the storm and then decreased around midnight. At an altitude of 610 km, the concentration of H + and O + , and the ratio of H + over electron density all exhibited large variations. The ratio of H + over electron density changed from less than 10% to more than 80% in a matter of 2 hours in the morning of 6 August. One explanation for such a behavior is that vertical transport dominates over charge exchange late at night due to the lower concentration of O + .

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“…This reaction mainly controls the production and loss of H + in the topside ionosphere [ Garzon et al ., ]. During our observation, [O + ] was much larger than [H + ] most of the time.…”

Section: The Topside Ionosphere Responsementioning

confidence: 59%

“…Garzon et al . [] found that a large drop of transition height (where O + and H + ion densities are equal) occurred soon after the peak of a moderate storm.…”

Section: Introductionmentioning

confidence: 99%

The F region and topside ionosphere response to a strong geomagnetic storm at Arecibo

et al. 2013

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“…), the processed data shown in this paper have been decomposed in time and altitude following the procedure applied by Garzon et al . [] and Goncharenko et al . [] and reconstructed without the high‐frequency variations and averaged at 30 min.…”

Section: Experimental Techniquementioning

confidence: 99%

Measurements of the O⁺ to H⁺ transition height and ion temperatures in the lower topside ionosphere over Arecibo for equinox conditions during the 2008–2009 extreme solar minimum

et al. 2013

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[1] We present incoherent scatter radar measurements of electron density, electron and ion temperatures, and ion composition made at Arecibo Observatory (18.35°N, 66.75°W), which is at a geomagnetic latitude of 30°N (or 46.7°dip latitude), during the recent extreme solar minimum of [2007][2008][2009] and find agreement between our data and recent reports of corresponding satellite observations. Both the in situ spacecraft measurements and our ground-based radar profiles exhibit unusually low electron densities and cold temperatures. These two factors result in an extraordinarily contracted ionosphere and thermosphere. This contraction in the ionosphere in turn causes the O + /H + transition height to descend; thus, the base of the low-latitude plasmasphere, or protonosphere, is found at extraordinary low altitudes. We show that during the geomagnetically quiet period of October 2009, the transition height h t , where, was observed at altitudes as low as 800-820 km during daytime and descended as low as 450 km during the night. At night, when T e = T i = T n , temperatures below 675 K were measured at 03:00 Atlantic Standard Time. These values are about 100 K lower than corresponding temperatures observed by the Arecibo incoherent scatter radar during the previous solar minimum period (1995)(1996)(1997).

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“…During solar maximum, the ionosphere at DMSP altitude (~800 km) is typically dominated by O + , while during solar minimum, it is dominated by H+. As mentioned in the introduction, the H + /O + transition height can vary significantly during the solar cycle, seasonally, and during geomagnetic storms [e.g., Garzon et al , ; Hysell et al , ] due to thermospheric heating and winds, and electric fields. This transition height can be above or below the DMSP spacecraft depending on these drivers.…”

Section: Datamentioning

confidence: 99%

“…O + dominates the ionosphere below the O + /H + transition height where the ionosphere transitions from an O + dominated plasma to an H + dominated plasma. This transition height can vary significantly during the solar cycle, seasonally, and during geomagnetic storms [e.g., Garzon et al , ; Hysell et al , ] due to thermospheric heating and winds, and electric fields. The other major constituent in the topside ionosphere is He + .…”

Section: Introductionmentioning

confidence: 99%

Topside ionospheric response to solar EUV variability

Anderson

Hawkins

2016

JGR Space Physics

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We present an analysis of 23 years of thermal plasma measurements in the topside ionosphere from the Defense Meteorological Satellite Program (DMSP) spacecraft. The H+/O+ ratio and density vary dramatically with the solar cycle; cross‐correlation coefficients between E10.7 and the daily averaged densities are greater than 0.85. The ionospheric parameters also vary dramatically with season, particularly at latitudes away from the equator where the solar zenith angle varies greatly with season. There are also 27 day solar rotation periodicities in the density, associated with periodicities in the directly measured solar EUV flux. Empirical orthogonal function analysis captures over 95% of the variation in the density in the first two principal components. The first principal component (PC1) is clearly associated with the solar EUV while the second principal component (PC2) is clearly associated with the solar zenith angle variation. The magnitude of the variation of the response of the topside ionosphere to solar EUV variability is shown to be closely related to the ionospheric composition. This is interpreted as the result of the effect of composition on the scale height in the topside ionosphere and the “pivot effect” in which the variation in density near the F2 peak is amplified by a factor of e at an altitude a scale height above the F2 peak. When the topside ionosphere is H+ dominated during solar minimum, DMSP may be much less than a scale height above the F2 peak while during solar maximum, when it is O+ dominated, DMSP may be several scale heights above the F2 peak.

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Response of the topside ionosphere over Arecibo to a moderate geomagnetic storm

Cited by 14 publications

References 23 publications

The F region and topside ionosphere response to a strong geomagnetic storm at Arecibo

The F region and topside ionosphere response to a strong geomagnetic storm at Arecibo

Measurements of the O⁺ to H⁺ transition height and ion temperatures in the lower topside ionosphere over Arecibo for equinox conditions during the 2008–2009 extreme solar minimum

Topside ionospheric response to solar EUV variability

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Response of the topside ionosphere over Arecibo to a moderate geomagnetic storm

Cited by 14 publications

References 23 publications

The F region and topside ionosphere response to a strong geomagnetic storm at Arecibo

The F region and topside ionosphere response to a strong geomagnetic storm at Arecibo

Measurements of the O+ to H+ transition height and ion temperatures in the lower topside ionosphere over Arecibo for equinox conditions during the 2008–2009 extreme solar minimum

Topside ionospheric response to solar EUV variability

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Measurements of the O⁺ to H⁺ transition height and ion temperatures in the lower topside ionosphere over Arecibo for equinox conditions during the 2008–2009 extreme solar minimum