Quantitatively estimating the energy input from the solar wind into the magnetosphere on a global scale is still an observational challenge. We perform three-dimensional magnetohydrodynamic (MHD) simulations to derive the energy coupling function. Based on 240 numerical test runs, the energy coupling function is given by E in = 3.78 × 10 7 n 0.24We study the correlations between the energy coupling function and a wide variety of magnetospheric activity, such as the indices of Dst, Kp, ap, AE, AU, AL, the polar cap index, and the hemispheric auroral power. The results indicate that this energy coupling function gives better correlations than the function. This result is also applied to a storm event under northward interplanetary magnetic field conditions. About 13% of the solar wind kinetic energy is transferred into the magnetosphere and about 35% of the input energy is dissipated in the ionosphere, consistent with previous studies.

[1] A statistical survey of 379 interplanetary magnetic field (IMF) southward turning events during the time period from 1995 to 2011 is performed to study the impact of solar wind conditions on the substorm growth phase duration and intensity. Substorm growth phase persists from several minutes up to 2-3 h, and its duration is mainly controlled by solar wind conditions. The larger dayside reconnection E-field and solar wind speed are, the shorter the growth phase will be. The lower limits of solar wind reconnection E-field and bulk speed for substorm occurrence are found to be 0.6 mV/m and 280 km/s, respectively. Similarly, the substorm intensity is linearly correlated to the dayside reconnection E-field. However, it seems to be independent of the amount of dayside geomagnetic flux reconnected and solar wind energy entered into the magnetosphere during the growth phase. Furthermore, all the events are divided into three groups for different averages of dayside reconnection E-field during the growth phase (E KL ):(1) 0.0 Ä E KL < 1.5 mV/m; (2) 1.5 Ä E KL < 2.5 mV/m; and (3) E KL 2.5 mV/m, and the geometric means of growth phase duration and auroral power maximum for these three groups are 91 min, 62 min, 32 min, and 35 GW, 51 GW, 74 GW, respectively. Citation: Li, H., C. Wang, and Z. Peng (2013), Solar wind impacts on growth phase duration and substorm intensity: A statistical approach,

This study analyzes strong sporadic E layer (Es) formation in Boa Vista (BV, 2.8°N, 60.7°W, dip: 18°), a low‐latitude region in the Brazilian sector, which occurred far after the onset of a magnetic storm recovery phase. Such occurrences were observed during seven magnetic storms with available data for BV. Thus, the ionospheric behavior on days around the magnetic storm that occurred on 20 January 2016 was investigated to search for possible explanations. This analysis indicated that the probable mechanism acting during the Es layer strengthening is the zonal westward electric field caused by a disturbance dynamo. The same evidence was also observed in two other magnetic storms at the same location. Hence, a numerical model of the E region dynamics, called MIRE (Portuguese acronym for E Region Ionospheric Model), was used to confirm whether the disturbance dynamo could cause the Es layer intensification. The inputs for the model were the electric field deduced from the vertical drift and the wind components provided by GSWM‐00 model. The simulations indicate that the Es layer density is significantly enhanced when the zonal electric field is present compared to the reference scenario with only the winds. Therefore, it is concluded that the disturbance dynamo electric field is the likely cause of the strong Es layers in the analyzed cases. Finally, the combined results from the model and observational data seem to contribute significantly to advance our understanding of the role of the electric fields in the Es layer formation at low latitudes.