Simulation of the pre‐reversal enhancement in the low latitude vertical ion drifts

Fesen, C. G.; Crowley, G.; Roble, R. G.; Richmond, A. D.; Fejer, Bela G.

doi:10.1029/2000gl000061

Cited by 181 publications

(189 citation statements)

References 15 publications

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“…A verification of this possibility, however, requires spatial measurements of E region conductivity for which we have no experimental evidence. Based on simulation, it was shown by Fesen et al [2000] that electron densities greater than 10 4 electrons/cm 3 preclude the PRE by short-circuiting the F region dynamo field [Rishbeth, 1971], the primary driver of the PRE. Therefore, the observed difference in the postsunset height rise of the F region mentioned earlier can be explained on the basis of E s observations from low latitude.…”

Section: Discussionmentioning

confidence: 99%

On the nature of low‐latitude E_s influencing the genesis of equatorial plasma bubble

et al. 2013

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[1] The potential influence of the postsunset low-latitude sporadic E (E s ) on the genesis of equatorial plasma bubble (EPB) has been investigated using observations made with the Gadanki radar and two ionosondes, one located at the magnetic equator providing the F layer characteristics and another at magnetically low-latitude providing the E s parameters. Observations revealed that the occurrence of EPB was associated with either the disruption of E s or presence of nonblanketing-type E s or intermittently occurring blanketing E s at low-latitude. In contrast, when blanketing E s occurred for a relatively long duration in the sunset hours, EPB did not occur. Model computation clearly reveals that the growth of the Rayleigh-Taylor instability depends very much on the thickness, height, and shape of electron density profile of the E s layer. The above findings thus suggest that low-latitude E s variability plays decisive role on the day-to-day variability of EPB through the growth rate of the Rayleigh-Taylor instability.

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Section: Discussionmentioning

confidence: 99%

On the nature of low‐latitude E_s influencing the genesis of equatorial plasma bubble

et al. 2013

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“…Previous observations and theoretical analyses show that drifts should be predominantly upward between 17:00 and 20:00 LT (e.g. Scherliess and Fejer, 1999;Fesen et al, 2000). Stoneback et al (2011), however, analyzed C/NOFS IVM measurements made between 2008 and 2010 and found large downward average drifts in the afternoon (16:00-18:00 LT) in all longitude sectors and seasons.…”

Section: Mean Vertical Driftsmentioning

confidence: 99%

Radar and satellite investigations of equatorial evening vertical drifts and spread <i>F</i>

2015

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Abstract. We analyzed pre-midnight equatorial F region observations made by the 30 MHz coherent backscatter radar of São Luis, Brazil between August 2010 and February 2012. These measurements were processed, and used to create monthly maps of the echo occurrence as a function of local time and height. The maps show the inter-annual variability associated with equatorial spread F (ESF) occurrence in the Brazilian longitude sector. We also constructed monthly curves of the evening vertical drifts, for the Brazilian sector, using measurements by the ion velocity meter (IVM) onboard the C/NOFS satellite. The IVM evening drifts show a good overall agreement with the Scherliess and Fejer (1999) empirical model. Measured and model drifts show the development of the pre-reversal enhancement (PRE) of the vertical plasma drifts during ESF season. Using joint radar and satellite measurements, we found that evening (18:00-18:30 LT) mean non-negative drifts provide a necessary but not sufficient condition for the occurrence of topside ESF echoes. Evening downward (negative) drifts preceded the absence of topside ESF irregularities.

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“…During higher solar activity years (2001)(2002)(2003)(2004), the WN4 pattern at the EIA crest region can also be found between 18:00 and 21:00 LT. This could be explained by the pre-reversal enhancement (PRE), which is defined as a sharp increase in vertical ion drift after sunset via an enhancement of the eastward electric field strength in the F region (e.g., Woodman, 1970;Fesen et al, 2000). The increased E × B drift will cause an electron density trough above the dip equator.…”

Section: Nonmigrating Tides At Low Latitudesmentioning

confidence: 99%

The solar activity dependence of nonmigrating tides in electron density at low and middle latitudes observed by CHAMP and GRACE

et al. 2016

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Abstract. In this paper we use more than a decade of in situ electron density observations from CHAMP and GRACE satellites to investigate the solar activity dependence of nonmigrating tides at both low and middle latitudes. The results indicate that the longitudinal patterns of F region electron density vary with season and latitude, which are exhibiting a wavenumber 4 (WN4) pattern around September equinox at low latitudes and WN1/WN2 patterns during local summer at the southern/northern middle latitudes. These wave patterns in the F region ionosphere can clearly be seen during both solar maximum and minimum years. At low latitudes the absolute amplitudes of DE3 (contributing to the WN4 pattern) are found to be highly related to the solar activity, showing larger amplitudes during solar maximum years. Similarly a solar activity dependence can also be found for the absolute amplitudes of D0, DW2 and DE1 (contributing to the WN1 and WN2 pattern) at middle latitudes. The relative amplitudes (normalized by the zonal mean) of these nonmigrating tides at both low and middle altitudes show little dependence on solar activity. We further found a clear modulation by the quasi-biennial oscillation (QBO) of the relative DE3 amplitudes in both satellite observations, which is consistent with the QBO dependence as reported for the E region temperatures and zonal wind. It also supports the strong coupling of the low-latitude nonmigrating tidal activity between the E and F regions. However, the QBO dependence cannot be found for the relative amplitudes of the nonmigrating tides at middle latitudes, which implies that these tides are generated in situ at F region altitudes.

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Simulation of the pre‐reversal enhancement in the low latitude vertical ion drifts

Cited by 181 publications

References 15 publications

On the nature of low‐latitude E_s influencing the genesis of equatorial plasma bubble

On the nature of low‐latitude E_s influencing the genesis of equatorial plasma bubble

Radar and satellite investigations of equatorial evening vertical drifts and spread <i>F</i>

The solar activity dependence of nonmigrating tides in electron density at low and middle latitudes observed by CHAMP and GRACE

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Simulation of the pre‐reversal enhancement in the low latitude vertical ion drifts

Cited by 181 publications

References 15 publications

On the nature of low‐latitude Es influencing the genesis of equatorial plasma bubble

On the nature of low‐latitude Es influencing the genesis of equatorial plasma bubble

Radar and satellite investigations of equatorial evening vertical drifts and spread &lt;i&gt;F&lt;/i&gt;

The solar activity dependence of nonmigrating tides in electron density at low and middle latitudes observed by CHAMP and GRACE

Contact Info

Product

Resources

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On the nature of low‐latitude E_s influencing the genesis of equatorial plasma bubble

On the nature of low‐latitude E_s influencing the genesis of equatorial plasma bubble

Radar and satellite investigations of equatorial evening vertical drifts and spread <i>F</i>