Electrodynamic coupling processes between the magnetosphere and the equatorial ionosphere during a 5-day HILDCAA event

Koga, D.; Sobral, J. H. A.; González, W. D.; Arruda, Daniela Cristina Santana; Abdu, M. A.; Castilho, V. M.; Mascarenhas, M.; Gonzalez, Alicia Clua de; Tsurutani, B. T.; Denardini, Clezio Marcos; Zamlutti, C. J.

doi:10.1016/j.jastp.2010.09.002

Cited by 16 publications

(18 citation statements)

References 28 publications

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“…On the other hand, as discussed earlier, the criteria adopted to classify a HILDCAA phenomenon were extreme, and in this case we believe that the conditions observed on 27-30 March can provide a satisfactory scenario of the ionospheric responses. The same type of restriction in accomplishing all HILDCAA criteria was found in other studies (Koga et al, 2011). The maximum AE observed in this period was 1535 nT and the average value was 327.39 nT.…”

Section: Event Of 13-31 March 2013supporting

confidence: 81%

“…Several studies regarding this topic have been published and some also show the low-latitude responses (Tsurutani et al, 2004bSobral et al, 2006;Koga et al, 2011). Tsurutani and Gonzalez (1987) proposed some empirical definitions in order to establish the HILDCAA occurrence: (a) AE index must reach peaks greater than or equal to 1000 nT sometime during the event, (b) the event must have a duration of at least 2 days, (c) AE never drops below 200 nT for more than 2 h at a time, and (d) the auroral activity occurs outside the main phase of magnetic storms.…”

Section: P M De Siqueira Negreti Et Al: Total Electron Content Resmentioning

confidence: 99%

“…They suggested that the PPEF is responsible for a prompt (within several hours) ionospheric response during a CIR/HSS interval. There is evidence of prompt equatorial ionospheric response and continuously penetrating IEF (Wei et al, 2008;Koga et al, 2011) during HILDCAAs.…”

Section: P M De Siqueira Negreti Et Al: Total Electron Content Resmentioning

confidence: 99%

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Total electron content responses to HILDCAAs and geomagnetic storms over South America

2017

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Abstract. Total electron content (TEC) is extensively used to monitor the ionospheric behavior under geomagnetically quiet and disturbed conditions. This subject is of greatest importance for space weather applications. Under disturbed conditions the two main sources of electric fields, which are responsible for changes in the plasma drifts and for current perturbations, are the short-lived prompt penetration electric fields (PPEFs) and the longer-lasting ionospheric disturbance dynamo (DD) electric fields. Both mechanisms modulate the TEC around the globe and the equatorial ionization anomaly (EIA) at low latitudes. In this work we computed vertical absolute TEC over the low latitude of South America. The analysis was performed considering HILDCAA (high-intensity, long-duration, continuous auroral electrojet (AE) activity) events and geomagnetic storms. The characteristics of stormtime TEC and HILDCAA-associated TEC will be presented and discussed. For both case studies presented in this work (March and August 2013) the HILDCAA event follows a geomagnetic storm, and then a global scenario of geomagnetic disturbances will be discussed. Solar wind parameters, geomagnetic indices, O / N 2 ratios retrieved by GUVI instrument onboard the TIMED satellite and TEC observations will be analyzed and discussed. Data from the RBMC/IBGE (Brazil) and IGS GNSS networks were used to calculate TEC over South America. We show that a HILDCAA event may generate larger TEC differences compared to the TEC observed during the main phase of the precedent geomagnetic storm; thus, a HILDCAA event may be more effective for ionospheric response in comparison to moderate geomagnetic storms, considering the seasonal conditions. During the August HILDCAA event, TEC enhancements from ∼ 25 to 80 % (compared to quiet time) were observed. These enhancements are much higher than the quiet-time variability observed in the ionosphere. We show that ionosphere is quite sensitive to solar wind forcing and considering the events studied here, this was the most important source of ionospheric responses. Furthermore, the most important source of TEC changes were the long-lasting PPEFs observed on August 2013, during the HILDCAA event. The importance of this study relies on the peculiarity of the region analyzed characterized by high declination angle and ionospheric gradients which are responsible for creating a complex response during disturbed periods.

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Section: Event Of 13-31 March 2013supporting

confidence: 81%

Section: P M De Siqueira Negreti Et Al: Total Electron Content Resmentioning

confidence: 99%

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Total electron content responses to HILDCAAs and geomagnetic storms over South America

2017

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“…These effects are explained by the appearance of dawn-to-dusk electric fields in the dayside near-equatorial ionosphere which has received the name ''prompt penetrating electric fields'' or PPEFs. More recently, such strong ionospheric effects have been noted during magnetic storms (Sobral et al 1997(Sobral et al , 2001Sastri et al 2002;Tsurutani et al 2004Tsurutani et al , 2008aTsurutani et al , 2008bHuang et al 2005;Mannucci et al 2005Mannucci et al , 2008Koga et al 2011;Siqueira et al 2011). The importance of the latter is that during storms, the electric fields are more intense (Tsurutani et al 2004) and have longer durations up to hours (Huang et al 2005).…”

Section: Introductionmentioning

confidence: 97%

Extreme changes in the dayside ionosphere during a Carrington-type magnetic storm

Tsurutani

Verkhoglyadova

Mannucci

et al. 2012

J. Space Weather Space Clim.

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It is shown that during the 30 October 2003 superstorm, dayside O + ions were uplifted to DMSP altitudes (~850 km). Peak densities were~9 · 10 5 cm À3 during the magnetic storm main phase (peak Dst = À390 nT). By comparison the 1-2 September 1859 Carrington magnetic storm (peak Dst estimated at À1760 nT) was considerably stronger. We investigate the impact of this storm on the low-to mid-latitude ionosphere using a modified version of the NRL SAMI2 ionospheric code. It is found that the equatorial region (LAT = 0°± 15°) is swept free of plasma within 15 min (or less) of storm onset. The plasma is swept to higher altitudes and higher latitudes due to E · B convection associated with the prompt penetration electric field. Equatorial Ionization Anomaly (EIA) O + density enhancements are found to be located within the broad range of latitudes~± (25°-40°) at~500-900 km altitudes. Densities within these peaks are~6 · 10 6 oxygen ions-cm À3 at~700 km altitude, approximately +600% quiet time values. The oxygen ions at the top portions (850-1000 km) of uplifted EIAs will cause strong low-altitude satellite drag. Calculations are currently being performed on possible uplift of oxygen neutrals by ion-neutral coupling to understand if there might be further significant satellite drag forces present.

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“…Ionospheric effects of the HILDCAAs were studied by several authors Wei et al, 2008;Kelley and Dao, 2009;Koga et al, 2011;Silva et al, 2017). Koga et al (2011) showed that the interplanetary electric field (IEF) is correlated with the variation of the F2-layer peak height in São Luís (44.6 • W, 2.33 • S), Brazil, during the HILDCAAs.…”

Section: Introductionmentioning

confidence: 99%

Cross-correlation and cross-wavelet analyses of the solar wind IMF B_z and auroral electrojet index AE coupling during HILDCAAs

Souza

Echer

Bolzan³

et al. 2018

Ann. Geophys.

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Abstract. Solar-wind-geomagnetic activity coupling during high-intensity long-duration continuous AE (auroral electrojet) activities (HILDCAAs) is investigated in this work. The 1 min AE index and the interplanetary magnetic field (IMF) B z component in the geocentric solar magnetospheric (GSM) coordinate system were used in this study. We have considered HILDCAA events occurring between 1995 and 2011. Cross-wavelet and cross-correlation analyses results show that the coupling between the solar wind and the magnetosphere during HILDCAAs occurs mainly in the period ≤ 8 h. These periods are similar to the periods observed in the interplanetary Alfvén waves embedded in the high-speed solar wind streams (HSSs). This result is consistent with the fact that most of the HILDCAA events under present study are related to HSSs. Furthermore, the classical correlation analysis indicates that the correlation between IMF B z and AE may be classified as moderate (0.4-0.7) and that more than 80 % of the HILDCAAs exhibit a lag of 20-30 min between IMF B z and AE. This result corroborates with Tsurutani et al. (1990) where the lag was found to be close to 20-25 min. These results enable us to conclude that the main mechanism for solar-wind-magnetosphere coupling during HILDCAAs is the magnetic reconnection between the fluctuating, negative component of IMF B z and Earth's magnetopause fields at periods lower than 8 h and with a lag of about 20-30 min.

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Electrodynamic coupling processes between the magnetosphere and the equatorial ionosphere during a 5-day HILDCAA event

Cited by 16 publications

References 28 publications

Total electron content responses to HILDCAAs and geomagnetic storms over South America

Total electron content responses to HILDCAAs and geomagnetic storms over South America

Extreme changes in the dayside ionosphere during a Carrington-type magnetic storm

Cross-correlation and cross-wavelet analyses of the solar wind IMF B_z and auroral electrojet index AE coupling during HILDCAAs

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Electrodynamic coupling processes between the magnetosphere and the equatorial ionosphere during a 5-day HILDCAA event

Cited by 16 publications

References 28 publications

Total electron content responses to HILDCAAs and geomagnetic storms over South America

Total electron content responses to HILDCAAs and geomagnetic storms over South America

Extreme changes in the dayside ionosphere during a Carrington-type magnetic storm

Cross-correlation and cross-wavelet analyses of the solar wind IMF Bz and auroral electrojet index AE coupling during HILDCAAs

Contact Info

Product

Resources

About

Cross-correlation and cross-wavelet analyses of the solar wind IMF B_z and auroral electrojet index AE coupling during HILDCAAs