scholarly journals Solar cycle variation of coronal mass ejections contribution to solar wind mass flux

2018 ◽  
Vol 13 (S340) ◽  
pp. 175-176 ◽  
Author(s):  
Wageesh Mishra ◽  
Nandita Srivastava ◽  
Zavkiddin Mirtoshev ◽  
Yuming Wang
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Coronal Mass Ejections ◽  
Mass Flux ◽  
Occurrence Rate ◽  
Solar Cycles ◽  
Solar Cycle Variation ◽  
The Earth ◽  
Solar Wind Parameters

AbstractCoronal Mass Ejections (CMEs) contribute to the perturbation of solar wind in the heliosphere. Thus, depending on the different phases of the solar cycle and the rate of CME occurrence, contribution of CMEs to solar wind parameters near the Earth changes. In the present study, we examine the long term occurrence rate of CMEs, their speeds, angular widths and masses. We attempt to find correlation between near sun parameters of the CMEs with near the Earth measurements. Importantly, we attempt to find what fraction of the averaged solar wind mass near the Earth is provided by the CMEs during different phases of the solar cycles.

scholarly journals Long-term correlations in solar proxies and solar wind parameters

2021 ◽  
Author(s):  
Luca Giovannelli ◽  
Raffaele Reda ◽  
Tommaso Alberti ◽  
Francesco Berrilli ◽  
Matteo Cantoresi ◽  
...  
Keyword(s):  
Solar Wind ◽  
Time Lag ◽  
Magnetic Activity ◽  
Time Shift ◽  
Time Interval ◽  
Solar Cycles ◽  
K Index ◽  
The Earth ◽  
Solar Wind Parameters

<p>The long-term behaviour of the Solar wind and its impact on the Earth are of paramount importance to understand the framework of the strong transient perturbations (CMEs, SIRs). Solar variability related to its magnetic activity can be quantified by using synthetic indices (e.g. sunspots number) or physical ones (e.g. chromospheric proxies). In order to connect the long-term solar activity variations to solar wind properties, we use Ca II K index and solar wind OMNI data in the time interval between 1965 and 2019, which almost entirely cover the last 5 solar cycles. A time lag in the correlation between the parameters is found. This time shift seems to show a temporal evolution over the different solar cycles.</p><div> </div>

scholarly journals Solar Cycle Variation of Cosmic ray Intensity along with Interplanetary and Solar Wind Plasma Parameters

2008 ◽  
Vol 45 (3) ◽  
pp. 63-68 ◽  
Author(s):  
Rajesh Mishra ◽  
Rekha Agarwal ◽  
Sharad Tiwari
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar Cycle ◽  
Interplanetary Magnetic Field ◽  
Cosmic Ray ◽  
Solar Wind Plasma ◽  
Solar Cycles ◽  
Plasma Parameters ◽  
Solar Cycle Variation ◽  
Cosmic Ray Intensity

Solar Cycle Variation of Cosmic ray Intensity along with Interplanetary and Solar Wind Plasma ParametersGalactic cosmic rays are modulated at their propagation in the heliosphere by the effect of the large-scale structure of the interplanetary medium. A comparison of the variations in the cosmic ray intensity data obtained by neutron monitoring stations with those in geomagnetic disturbance, solar wind velocity (V), interplanetary magnetic field (B), and their product (V' B) near the Earth for the period 1964-2004 has been presented so as to establish a possible correlation between them. We used the hourly averaged cosmic ray counts observed with the neutron monitor in Moscow. It is noteworthy that a significant negative correlation has been observed between the interplanetary magnetic field, product (V' B) and cosmic ray intensity during the solar cycles 21 and 22. The solar wind velocity has a good positive correlation with cosmic ray intensity during solar cycle 21, whereas it shows a weak correlation during cycles 20, 22 and 23. The interplanetary magnetic field shows a weak negative correlation with cosmic rays for solar cycle 20, and a good anti-correlation for solar cycles 21-23 with the cosmic ray intensity, which, in turn, shows a good positive correlation with disturbance time index (Dst) during solar cycles 21 and 22, and a weak correlation for cycles 20 and 23.

Predicting Solar Disturbance Effects on Navigation Systems

1999 ◽  
Vol 52 (2) ◽  
pp. 203-216 ◽  
Author(s):  
M. Lockwood ◽  
M. N. Wild ◽  
R. Stamper ◽  
C. J. Davis ◽  
M. Grande
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Ionospheric Disturbances ◽  
Navigation Systems ◽  
Positioning Systems ◽  
Positioning Errors ◽  
The Earth ◽  
Operational Systems ◽  
Solar Disturbances

A variety of operational systems are vulnerable to disruption by solar disturbances brought to the Earth by the solar wind. Of particular importance to navigation systems are energetic charged particles which can generate temporary malfunctions and permanent damage in satellites. Modern spacecraft technology may prove to be particularly at risk during the next maximum of the solar cycle. In addition, the associated ionospheric disturbances cause phase shifts of transionospheric and ionosphere-reflected signals, giving positioning errors and loss of signal for GPS and Loran-C positioning systems and for over-the-horizon radars. We now have sufficient understanding of the solar wind, and how it interacts with the Earth's magnetic field, to predict statistically the likely effects on operational systems over the next solar cycle. We also have a number of advanced ways of detecting and tracking these disturbances through space but we cannot, as yet, provide accurate forecasts of individual disturbances that could be used to protect satellites and to correct errors. In addition, we have recently discovered long-term changes in the Sun, which mean that the number and severity of the disturbances to operational systems are increasing.

scholarly journals Solar Cycle-Modulated Deformation of the Earth–Ionosphere Cavity

2021 ◽  
Vol 9 ◽  
Author(s):  
Tamás Bozóki ◽  
Gabriella Sátori ◽  
Earle Williams ◽  
Irina Mironova ◽  
Péter Steinbach ◽  
...  
Keyword(s):  
Solar Cycle ◽  
High Latitude ◽  
Cavity Resonator ◽  
Lightning Activity ◽  
Electron Precipitation ◽  
Optical Observations ◽  
X Rays ◽  
Solar Cycle Variation ◽  
The Earth

The Earth–ionosphere cavity resonator is occupied primarily by the electromagnetic radiation of lightning below 100 Hz. The phenomenon is known as Schumann resonances (SR). SR intensity is an excellent indicator of lightning activity and its distribution on global scales. However, long-term measurements from high latitude SR stations revealed a pronounced in-phase solar cycle modulation of SR intensity seemingly contradicting optical observations of lightning from satellite, which do not show any significant solar cycle variation in the intensity and spatial distribution of lightning activity on the global scale. The solar cycle-modulated local deformation of the Earth–ionosphere cavity by the ionization of energetic electron precipitation (EEP) has been suggested as a possible phenomenon that may account for the observed long-term modulation of SR intensity. Precipitating electrons in the energy range of 1–300 keV can affect the Earth–ionosphere cavity resonator in the altitude range of about 70–110 km and modify the SR intensities. However, until now there was no direct evidence documented in the literature supporting this suggestion. In this paper we present long-term SR intensity records from eight stations, each equipped with a pair of induction coil magnetometers: five high latitude (|lat| > 60°), two mid-high latitude (50° < |lat| < 60°) and one low latitude (|lat| < 30°). These long-term, ground-based SR intensity records are compared on the annual and interannual timescales with the fluxes of precipitating 30–300 keV medium energy electrons provided by the POES NOAA-15 satellite and on the daily timescale with electron precipitation events identified using a SuperDARN radar in Antarctica. The long-term variation of the Earth–ionosphere waveguide’s effective height, as inferred from its cutoff frequency, is independently analyzed based on spectra recorded by the DEMETER satellite. It is shown that to account for all our observations one needs to consider both the effect of solar X-rays and EEP which modify the quality factor of the cavity and deform it dominantly over low- and high latitudes, respectively. Our results suggest that SR measurements should be considered as an alternative tool for collecting information about and thus monitoring changes in the ionization state of the lower ionosphere associated with EEP.

scholarly journals Long‐Term Variations in Solar Wind Parameters, Magnetopause Location, and Geomagnetic Activity Over the Last Five Solar Cycles

2019 ◽  
Vol 124 (6) ◽  
pp. 4049-4063 ◽  
Author(s):  
A. A. Samsonov ◽  
Y. V. Bogdanova ◽  
G. Branduardi‐Raymont ◽  
J. Safrankova ◽  
Z. Nemecek ◽  
...  
Keyword(s):  
Solar Wind ◽  
Geomagnetic Activity ◽  
Solar Cycles ◽  
Solar Wind Parameters ◽  
Long Term Variations

scholarly journals Time variations of the ionosphere at the northern tropical crest of ionization at Phu Thuy, Vietnam

2011 ◽  
Vol 29 (1) ◽  
pp. 197-207 ◽  
Author(s):  
H. Pham Thi Thu ◽  
C. Amory-Mazaudier ◽  
M. Le Huy
Keyword(s):  
Solar Cycle ◽  
Diurnal Variation ◽  
Sunspot Cycle ◽  
Solar Cycles ◽  
Maximum Phase ◽  
Solar Cycle Variation ◽  
Critical Frequency Fof2 ◽  
Semiannual Variation ◽  
Time Variations

Abstract. This study is the first which gives the climatology of the ionosphere at the northern tropical crest of ionization in the Asian sector. We use the data from Phu Thuy station, in Vietnam, through three solar cycles (20, 21 and 22), showing the complete morphology of ionosphere parameters by analyzing long term variation, solar cycle variation and geomagnetic activity effects, seasonal evolution and diurnal development. Ionospheric critical frequencies, foF2, foF1 and foE, evolve according to the 11-year sunspot cycle. Seasonal variations show that foF2 exhibits a semiannual pattern with maxima at equinox, and winter and equinoctial anomalies depending on the phases of the sunspot solar cycle. ΔfoF2 exhibits a semiannual variation during the minimum phase of the sunspot solar cycle 20 and the increasing and decreasing phases of solar cycle 20, 21 and 22. ΔfoF1 exhibits an annual variation during the maximum phase of solar cycles 20, 21 and 22. Δh'F2 shows a regular seasonal variation for the different solar cycles while Δh'F1 exhibits a large magnitude dispersion from one sunspot cycle to another. The long term variations consist in an increase of 1.0 MHz for foF2 and of 0.36 MHz for foF1. foE increases 0.53 MHz from solar cycle 20 to solar cycle 21 and then decreases −0.23 MHz during the decreasing phase of cycle 21. The diurnal variation of the critical frequency foF2 shows minima at 05:00 LT and maxima around 14:00 LT. foF1 and foE have a maximum around noon. The diurnal variation of h'F2 exhibits a maximum around noon. The main features of h'F1 are a minimum near noon and the maximum near midnight. Other minima and maxima occur in the morning, at about 04:00 or 05:00 LT and in the afternoon, at about 18:00 or 19:00 LT but they are markedly smaller. Only during the maximum phase of all sunspot solar cycles the maximum near 19:00 LT is more pronounced.

scholarly journals Solar-cycle variation of low density solar wind during more than three solar cycles

2000 ◽  
Vol 27 (23) ◽  
pp. 3761-3764 ◽  
Author(s):  
I. G. Richardson ◽  
D. Berdichevsky ◽  
M. D. Desch ◽  
C. J. Farrugia
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Low Density ◽  
Solar Cycles ◽  
Solar Cycle Variation ◽  
Cycle Variation

Deep Neural Networks With Convolutional and LSTM Layers for SYM-H and ASY-H Forecasting

2021 ◽  
Author(s):  
Armando Collado ◽  
Pablo Muñoz ◽  
Consuelo Cid
Keyword(s):  
Neural Networks ◽  
Solar Wind ◽  
Deep Neural Networks ◽  
Geomagnetic Disturbance ◽  
Solar Cycles ◽  
Great Precision ◽  
Geomagnetic Indices ◽  
The Earth ◽  
Solar Wind Parameters ◽  
The Magnetic Field

<p>Geomagnetic indices quantify the disturbance caused by the solar activity in particular regions of the Earth. Among them, the SYM-H and ASY-H indices represent the (longitudinally) symmetric and asymmetric geomagnetic disturbance of the horizontal component of the magnetic field at mid-latitude with a 1-minute resolution. Their resolution, along with their relation to the solar wind parameters, makes the forecasting of the geomagnetic indices a problem that can be addressed through the use of Deep Learning, particularly using Deep Neural Networks (DNN). In this work, we present two DNNs developed to forecast the SYM-H and ASY-H indices. Both networks have been trained using solar wind data from the last two solar cycles and they are able to accurately forecast the indices two hours in advance, considering the solar wind and indices values for the previous 16 hours. The evaluation of both networks reveals a great precision for the forecasting, including good predictions for large storms that occurred during the solar cycle 23.</p>

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