The Polar Cap (PC) indices: Relations to solar wind parameters and global magnetic activity

2008 ◽  
Vol 70 (18) ◽  
pp. 2246-2261 ◽  
Author(s):  
P. Stauning ◽  
Oleg Troshichev ◽  
Alexander Janzhura
Keyword(s):  
Solar Wind ◽  
Magnetic Activity ◽  
Polar Cap ◽  
Solar Wind Parameters

Space Weather Monitoring Based on Surface Magnetic Observations (РС Index)

2021 ◽  
Vol 3 ◽  
pp. 12-27
Author(s):  
О. А. Troshichev ◽  
◽  
D. A. Sormakov ◽  
Keyword(s):  
Solar Wind ◽  
Measurement Data ◽  
Magnetic Activity ◽  
Real Field ◽  
Lagrange Point ◽  
Polar Cap ◽  
Independent Analysis ◽  
Solar Wind Parameters ◽  
The Impact ◽  
Independent Indicator

Polar cap magnetic activity (РС index) is an indicator of solar wind energy that enters the magnetosphere (Resolutions of XXII IAGA Assembly, 2013). Usually, the PC index follows changes in the interplanetary electric field EKL, that is estimated from measurement data on solar wind parameters at the Lagrange point L1 (available at the OMNI website). However, during the period of magnetic field perturbations, the correspondence between EKL and PC is often disturbed. To reveal the regularity of disturbances, the correlation was analyzed between the PC index and the computed field EKL during magnetic substorms, which are considered as an independent indicator of the impact of perturbed solar wind on the magnetosphere. The independent analysis for the PCN and PCS indices demonstrated that the magnetic activity in the winter polar cap (PCwinter) provides statistically more correct results than the magnetic activity in the summer cap (PCsummer). The correlation between the PCwinter and the computed field EKL (R > 0.5) was observed for ~80% of the analyzed substorms. In the other cases (20%), the correlation was low or even negative, even though substorms were evidently associated with the PC index growth. So, in these cases, the computed field EKL did not contact with the magnetosphere. Hence, the PC index allows verifying the real field EKL affecting the magnetosphere and checking in such way whether the solar wind registered at the Lagrange point contacted with the magnetosphere (data from the OMNI website).

scholarly journals Earth’s geomagnetic response to solar wind changes associated with solar events at low latitude regions at the TRE MAGDAS Station

2021 ◽  
Vol 880 (1) ◽  
pp. 012009
Author(s):  
R Umar ◽  
S N A Syed Zafar ◽  
N H Sabri ◽  
M H Jusoh ◽  
A Yoshikawa ◽  
...  
Keyword(s):  
Solar Wind ◽  
Geomagnetic Storms ◽  
Interplanetary Space ◽  
Coronal Holes ◽  
Magnetic Activity ◽  
Study Results ◽  
Geomagnetic Fields ◽  
Solar Events ◽  
Solar Wind Parameters ◽  
Mass Ejection

Abstract The Sun’s magnetic activity influences disturbances that perturb interplanetary space by producing large fluxes of energetic protons, triggering geomagnetic storms and affecting the ground geomagnetic field. The effect of two solar events, namely Coronal Mass Ejection (CME) and Coronal Holes, on geomagnetic indices (SYM/H), solar wind parameters and ground geomagnetic fields has provided magnetic ground data, which were extracted from the Terengganu (TRE, -4.21° N, 175.91° E) Magnetometer (MAGDAS) station, and investigated in this study. Results show that the physical dynamic mechanism in the Earth’s magnetosphere is triggered by various solar wind parameters associated with CMEs and Coronal hole events during the minimum solar cycle of 24 at low latitudes. It is important to study solar wind-magnetosphere coupling because it has an impact on ground-based technological systems and human activities.

scholarly journals Invariability of relationship between the polar cap magnetic activity and geoeffective interplanetary electric field

2011 ◽  
Vol 29 (8) ◽  
pp. 1479-1489 ◽  
Author(s):  
O. A. Troshichev ◽  
N. A. Podorozhkina ◽  
A. S. Janzhura
Keyword(s):  
Solar Wind ◽  
Solar Activity ◽  
Electric Field ◽  
Solar Minimum ◽  
Solar Maximum ◽  
Magnetic Activity ◽  
Polar Cap ◽  
Polar Caps ◽  
The Relationship ◽  
Wind Energy Input

Abstract. The PC (polar cap) index characterizing the solar wind energy input into the magnetosphere is calculated with use of parameters α, β, and φ, determining the relationship between the interplanetary electric field (EKL) and the value of magnetic activity δF in the polar caps. These parameters were noted as valid for large and small EKL values, and as a result the suggestion was made (Troshichev et al., 2006) that the parameters should remain invariant irrespective of solar activity. To verify this suggestion, the independent sets of calibration parameters α, β, and φ were derived separately for the solar maximum (1998–2001) and solar minimum (1997, 2007–2009) epochs, with a proper choice of a quiet daily variation (QDC) as a level of reference for the polar cap magnetic activity value. The results presented in this paper demonstrate that parameters α, β, and φ, derived under conditions of solar maximum and solar minimum, are indeed in general conformity and provide consistent (within 10 % uncertainty) estimations of the PC index. It means that relationship between the geoeffective solar wind variations and the polar cap magnetic activity responding to these variations remains invariant irrespective of solar activity. The conclusion is made that parameters α, β, and φ derived in AARI#3 version for complete cycle of solar activity (1995–2005) can be regarded as forever valid.

scholarly journals Polar Cap Potential and Merging Electric Field during High Intensity Long Duration Continuous Auroral Activity

2016 ◽  
Vol 3 (1) ◽  
pp. 6 ◽  
Author(s):  
Binod Adhikari ◽  
Narayan P. Chapagain
Keyword(s):  
Solar Wind ◽  
Wavelet Transform ◽  
Electric Field ◽  
High Intensity ◽  
Cross Correlation ◽  
Auroral Electrojet ◽  
Polar Cap ◽  
Auroral Activity ◽  
Long Duration ◽  
Solar Wind Parameters

<p>The polar cap potential (PCV) has long been considered as a key parameter for describing the state of the magnetosphere/ionosphere system. The relationship between the solar wind parameters and the PCV is important to understand the coupling process between solar wind-magnetosphere-ionosphere. In this work, we have estimated PCV and merging electric field (Em) during two different high intensity long duration continuous auroral activity (HILDCAA) events. For each event, we examine the solar wind parameters, magnitude of interplanetary magnetic field (IMF), interplanetary electric field (IEF), PCV, Em and geomagnetic indices (i.e., SYM-H, geomagnetic auroral electrojet (AE) index, polar cap index (PCI) and auroral electrojet index lower (AL), respectively). We also study the role of PCI and AL indices to monitor polar cap (PC) activity during HILDCAAs. In order to verify their role, we use wavelet transform and cross-correlation techniques. For the three events studied here, the results obtained from continuous wavelet transform (CWT) and discrete wavelet transform (DWT) are different, however the effect of HILDCAA can be easily identified. We also observe the cross-correlation of PCI and PCV with AL, SYM-H, Bz component of the IMF and Ey component of the IEF individually. Both PCI and PCV show very good correlation with AL and SYM-H indices during the events. Observing these results, it can be suggested that PCI and AL indices play a significant role to monitor geomagnetic activity generated by geoeffective solar wind parameters.</p><p>Journal of Nepal Physical Society Vol.3(1) 2015: 6-17</p>

scholarly journals Solar Wind Parameters and Its Geoefficiency During Minimums of Four Solar Cycles

2021 ◽  
Vol 31 (4) ◽  
pp. 508-514
Author(s):  
Vitalii Degtyarev ◽  
Georgy Popov ◽  
Svetlana Chudnenko
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar Activity ◽  
Geomagnetic Activity ◽  
Statistical Processing ◽  
Magnetic Activity ◽  
Solar Cycles ◽  
Deep Minimum ◽  
Significant Difference ◽  
Solar Wind Parameters

Recently a number of publications have appeared on the long and deep minimum in cycle 23 of solar activity. This interest is due to the fact that it turned out to be the longest and deepest in terms of the number of sunspots in the entire era of space exploration. The features of the minimum of cycle 23 of solar activity and the beginning of cycle 24 made it possible to assume that in the coming decades, a minimum of solar activity similar to the Dalton or Maunder minimum, leading to a global change in the earth's climate, may occur. Such assumptions make a detailed study of the influence of the minimum of solar cycle 23 on the parameters of the solar wind and the interplanetary magnetic field, as well as a comparison of this influence with similar manifestations in the three previous cycles very urgent. The work carried out statistical processing and analysis of data available in print and on the Internet on the indices of solar activity (W and F10.7), on geomagnetic activity, as well as on the parameters of the solar wind and interplanetary field. In contrast to other similar studies, when choosing time intervals for all cycles, only one — 12 months was used, which made it possible to exclude annual and semi-annual variations in solar wind parameters. For the considered minima of solar activity, the geoeffectiveness of the disturbed fluxes ICME, CIR, and Sheath was considered. A monotonic and very significant decrease in the geoeffectiveness of the ICME streams was found. Data processing on the hourly average values of the solar wind parameters at the minima of geomagnetic activity for 4 cycles confirmed the significant difference between cycle 23 and the previous ones in the behavior of the magnetic field. The cycle-by-cycle decrease in the geoeffectiveness of coronal ejections discussed in the press deserves a more detailed analysis using extensive data on magnetic activity indices.

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