Relationship between solar wind dynamic pressure and amplitude of geomagnetic sudden commencement (SC)

Abstract

The local time variation of geomagnetic sudden commencements (SCs) has not been taken into account in the Siscoe's linear relationship which connects the SC amplitude with the corresponding dynamic pressure variation of the solar wind. By considering the physical background of SC, we studied which local time is best to extract the information of the solar wind dynamic pressure and concluded that the SC amplitude at 4-5 h local time of middleand low-latitude stations most directly reflects the dynamic pressure effect. This result is used to re-check the order of magnitude of the largest 3 SCs observed since 1868.

Geoelectric Field Evaluation During the September 2017 Geomagnetic Storm: MA.I.GIC. Model

“…The response at low latitudes is characterized by a double SI (black dotted vertical lines) and a double MP (red and green shaded regions) with a recovery phase lasting for ∼3 days. As expected, at those latitudes, the magnetospheric origin contribution is dominant (Alberti et al, ; Araki, ; Araki & Shinbori, ; Piersanti & Villante, ; Piersanti, Cesaroni, et al, ; Villante & Piersanti, ). In fact, the H component shows a behavior similar to Sym‐H index (Figure h), confirming the key role played by the magnetospheric ring current during the MP (Wanliss & Showalter, ).…”

“…Interplanetary coronal mass ejections (ICMEs) are the principal geoeffective solar disturbances (Gosling, ; Piersanti, Alberti, et al, ; Shen et al, ). Their leading edges usually drive shock waves, called interplanetary shocks (ISs; Araki & Shinbori, ; Lugaz et al, ; Oliveira et al, ; Piersanti et al, ). The impact of IS onto the magnetopause compresses the magnetosphere (Vellante et al, ; Villante & Piersanti, , ), causing a sudden increase in the geomagnetic field intensity, called a Sudden Impulse (SI), often followed by intense fluctuations of the magnetospheric field (Di Matteo & Villante, ; Piersanti et al, ; Villante et al, ; Zhang et al, ).…”

Use of spherical elementary currents to map the polar current systems associated with the geomagnetic sudden commencements on 2013 and 2015 St. Patrick's Day storms

“…Regarding low latitudes, the waveforms shown in Figure are consistent with Araki's model and are essentially explained by the residual contribution of DP‐associated FACs [e.g., Araki and Shinbori , ].…”

“…The DL eq subfield is determined from a single low-latitude observatory, Tamanrasset (TAM), after correction with the above sine law. Even if TAM may not be totally exempted from the DP perturbation, its location around dawn in both events makes it suitable according to the statistical method proposed by Araki and Shinbori [2016]. The final DL eq reaches moderate values near 30 nT and 40 nT for the X component of the 2013 and 2015 events, respectively.…”

Development of low power wireless fluxgate magnetometer instrumentation for real-time geomagnetic monitoring

“…The Earth's magnetic field magnitude is in the range of 20,000nT to 65,000nT depends on location point based on magnetic field contour line as can be seen in isodynamic chart from world magnetic model [5]. Exogenous effect on Earth's magnetic field can cause numerous consequences on natural and human made technology [6][7]. Satellite operation is strongly dictated by near-Earth orbit space weather condition [8].…”