Ionospheric disturbance dynamo associated to a coronal hole: Case study of 5–10 April 2010

Fathy, Ibrahim; Amory‐Mazaudier, Christine; Fathy, Adel; Mahrous, A.; Yumoto, K.; Ghamry, Essam

doi:10.1002/2013ja019510

Cited by 42 publications

(62 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This demonstrates that at this stage the Ddyn process becomes the dominant mechanism that restructures the ionospheric parameters (Amory‐Mazaudier et al, ). Similar observations of Ddyn were reported in the late recovery phase of the storm (Fathy et al, ). Earlier investigations of Ddyn reported longitudinal variability of Ddyn signature over African, American, and Asian sectors (longitudinal separation over 20°; Fathy et al, ; Le‐Huy & Amory‐Mazaudier, ; Zaka et al, ).…”

Section: Discussionsupporting

confidence: 88%

“…Similar observations of Ddyn were reported in the late recovery phase of the storm (Fathy et al, ). Earlier investigations of Ddyn reported longitudinal variability of Ddyn signature over African, American, and Asian sectors (longitudinal separation over 20°; Fathy et al, ; Le‐Huy & Amory‐Mazaudier, ; Zaka et al, ). Our investigation discusses this variability in longitudinal separation less than 20°.…”

Section: Discussionsupporting

confidence: 88%

“…Earlier investigations of Ddyn over American, African, and Asian sectors reported that intensity of the storm controls the magnitude of the Dp2 which appears higher than the Ddyn over the American and Asian sector in contrast to the African sector (Zaka et al, ). It has also been reported that the strongest effect of Ddyn was observed in the European‐African sector during April 2010 (Fathy et al, ). From the present investigation we find that signature of Ddyn is variable over 20° longitude separation.…”

Section: Discussionmentioning

confidence: 86%

“…The relative dominance of PP and Ddyn and their interaction over different phases of these storms still requires detailed investigations. This investigation is physically very significant as these phenomena can alter many ionospheric parameters like electron density, vertical plasma, drifts, and enhancement/reduction in eastward/westward electric field which leads to enhancement/reduction in the horizontal component of magnetic field (Bagiya et al, ; Fathy et al, ; Nava et al, ; Nayak et al, ; Sastri, ; Tulasi Ram et al, ). It should be noted that the present study is based on only the magnetic signatures at ground which cannot account for PP and Ddyn signatures at local night when the ionospheric conductivity is very small.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effect of Disturbance Electric Fields on Equatorial Electrojet Over Indian Longitudes

et al. 2018

View full text Add to dashboard Cite

Prompt penetration (PP) and ionospheric disturbance dynamo (Ddyn) are two expressions of the disturbed electric field developed during a geomagnetic storm in the Earth's ionosphere. Earlier investigations treated these two processes independently over longitudinal separation beyond 20°. In the present study, we investigate the conjunction of these phenomena on equatorial electrojet at 20° longitude separations using daytime magnetic field data from three equatorial sites viz., Minicoy, Vencode, and Campbell Bay and three low‐latitude sites viz., Alibag, Hyderabad, and Nabagram, located within 20° longitude over Indian region, during three intense storms (Dst <− 150 nT). We propose a statistical method to identify PP signatures from large data set. In addition, we distinguish the signatures of PP and Ddyn during early recovery phase of intense storms and compute pure Ddyn signature in the late recovery phase. It is seen that the effect of PP is similar at the three equatorial sites for each storm. We find that signatures of Ddyn are amplified at Minicoy and Vencode compared to Campbell Bay, and their magnitude decreases toward low‐latitude stations, also reflected in the current vector patterns. Our investigations of intense geomagnetic storms show that PP effect dominates the main phase, followed by a combined effect of PP and Ddyn in the early recovery phase. Eventually the Ddyn signature dominates in the late recovery phase with decreasing amplitudes of Ddyn with increasing time. Such investigations can provide new information about variations in ionospheric parameters.

show abstract

Section: Discussionsupporting

confidence: 88%

Section: Discussionsupporting

confidence: 88%

Section: Discussionmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of Disturbance Electric Fields on Equatorial Electrojet Over Indian Longitudes

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Fathy et al [2014], andNava et al [2016] characterized the DP2 and Ddyn. However, their inclusion into recent models at improving predictions accuracy of geomagnetic storm responses at equatorial latitudes is not yet implemented.Nava et al [2016] used all of the above discussed equations during St. Patrick's stormy day in March 2015, and they used wavelet analysis to separate DP2 and Ddyn.…”

mentioning

confidence: 99%

On the historical origins of the CEJ, DP2, and Ddyn current systems and their roles in the predictions of ionospheric responses to geomagnetic storms at equatorial latitudes

2017

View full text Add to dashboard Cite

In this short letter, we recall the differences between the counter electrojet (CEJ), which is a phenomenon observed on the magnetically quiet days and the disturbance dynamo (Ddyn), which can be observed during and after a geomagnetic storm. The CEJ is well known to occur near the geomagnetic dip equator. It can be identified by a reversal in the horizontal component (H) of the geomagnetic field daily regular variations. In contrast to equatorial electrojet (EEJ) that flows eastward in the daytime, the CEJ is considered to flow westward. The magnetic signatures of the reversed solar quiet (Sq) current at the low latitude during magnetic storms are due to the Ddyn. This disturbance (Ddyn) is produced by current systems that are driven by thermospheric storm winds originating from the Joule heating of enhanced high‐latitude currents. The DP2 is the magnetic effect of current systems at high latitudes. These currents are associated with the coupling of magnetosphere and ionosphere through geomagnetic field lines. They are associated to the magnetospheric convection. During intense magnetic storms these high‐latitude currents are enhanced and their magnetic effects can extend toward the low latitudes. This work shows that the study of magnetic perturbations makes it possible to understand the disturbances of the ionospheric electric currents. The use of an efficient treatment of the magnetic signals makes it possible to separate the magnetic effects of the different perturbations prompt penetration of the magnetospheric convection electric field and disturbance dynamo electric field. This was performed in the paper Nava et al. (2016).

show abstract

Middle‐ and low‐latitude ionosphere response to 2015 St. Patrick's Day geomagnetic storm

et al. 2016

View full text Add to dashboard Cite

This paper presents a study of the St Patrick's Day storm of 2015, with its ionospheric response at middle and low latitudes. The effects of the storm in each longitudinal sector (Asian, African, American, and Pacific) are characterized using global and regional electron content. At the beginning of the storm, one or two ionospheric positive storm effects are observed depending on the longitudinal zones. After the main phase of the storm, a strong decrease in ionization is observed at all longitudes, lasting several days. The American region exhibits the most remarkable increase in vertical total electron content (vTEC), while in the Asian sector, the largest decrease in vTEC is observed. At low latitudes, using spectral analysis, we were able to separate the effects of the prompt penetration of the magnetospheric convection electric field (PPEF) and of the disturbance dynamo electric field (DDEF) on the basis of ground magnetic data. Concerning the PPEF, Earth's magnetic field oscillations occur simultaneously in the Asian, African, and American sectors, during southward magnetization of the Bz component of the interplanetary magnetic field. Concerning the DDEF, diurnal magnetic oscillations in the horizontal component H of the Earth's magnetic field exhibit a behavior that is opposed to the regular one. These diurnal oscillations are recognized to last several days in all longitudinal sectors. The observational data obtained by all sensors used in the present paper can be interpreted on the basis of existing theoretical models.

show abstract

Ionospheric disturbance dynamo associated to a coronal hole: Case study of 5–10 April 2010

Cited by 42 publications

References 40 publications

Effect of Disturbance Electric Fields on Equatorial Electrojet Over Indian Longitudes

Effect of Disturbance Electric Fields on Equatorial Electrojet Over Indian Longitudes

On the historical origins of the CEJ, DP2, and Ddyn current systems and their roles in the predictions of ionospheric responses to geomagnetic storms at equatorial latitudes

Middle‐ and low‐latitude ionosphere response to 2015 St. Patrick's Day geomagnetic storm

Contact Info

Product

Resources

About