Singularity Detection on Forbush Decrease at High Latitude Stations During Geomagnetic Disturbances

2021 ◽  
Author(s):  
Roshan Kumar Mishra ◽  
Ashok Silwal ◽  
Rabin Baral ◽  
Binod Adhikari ◽  
Carlos Roberto Braga ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
Forbush Decrease ◽  
Cosmic Ray ◽  
Shielding Effect ◽  
Clear Correlation ◽  
Discrete Wavelet ◽  
Correlation Technique ◽  
H Index ◽  
Monitoring Stations ◽  
The Imf

Abstract We analyzed the behavior of Cosmic Ray (CR) intensity during geomagnetic events of different nature and strength, using ground-based CR measurements from the World Neutron Monitoring Stations Network. We took account of interplanetary triggers and the geo-effectiveness while choosing the events. Forbush Decrease (FD) was observed when the magnetic fields entangled in and around CME exerts a shielding effect on galactic cosmic radiation, causing a sudden reduction of count rate in the neutron monitors. The results revealed that the FD plunged between -4% and -20% in the chosen events. The FD examined was abnormal and a multi-stage decrement in FD was observed during the event period. The reduction in Cosmic ray intensity was found to be inversely proportional to the cut - off rigidity at the specified neutron monitoring stations. Furthermore, we have also used the Discrete Wavelet Transform (DWT) technique to detect singularity on Forbush decrease at the stations described. The first three decomposition levels have proved sufficient to isolate singularity patterns associated with Forbush decrease in conjunction with events of different nature and intensity, ranging from intense geomagnetic storm to super intense geomagnetic storm to HILDCAA event. Also, we found that the cosmic ray flux was correlated with the IMF-Bz values and the SYM-H index during the process, as indicated by the cross-correlation technique. No noticeable lag has been found between the parameters discussed, which indicates a clear correlation between the IMF Bz and the SYM-H index and the FD.

scholarly journals Survey of ortho-H2D+ in high-mass star-forming regions

2020 ◽  
Vol 644 ◽  
pp. A34
Author(s):  
G. Sabatini ◽  
S. Bovino ◽  
A. Giannetti ◽  
F. Wyrowski ◽  
M. A. Órdenes ◽  
...  
Keyword(s):  
Star Formation ◽  
Formation Process ◽  
Strong Dependence ◽  
Cosmic Ray ◽  
High Mass ◽  
Clear Correlation ◽  
Mass Star ◽  
Large Sample ◽  
Star Forming ◽  
Star Forming Regions

Context. Deuteration has been suggested to be a reliable chemical clock of star-forming regions due to its strong dependence on density and temperature changes during cloud contraction. In particular, the H3+ isotopologues (e.g. ortho-H2D+) seem to act as good proxies of the evolutionary stages of the star formation process. While this has been widely explored in low-mass star-forming regions, in the high-mass counterparts only a few studies have been pursued, and the reliability of deuteration as a chemical clock remains inconclusive. Aims. We present a large sample of o-H2D+ observations in high-mass star-forming regions and discuss possible empirical correlations with relevant physical quantities to assess its role as a chronometer of star-forming regions through different evolutionary stages. Methods. APEX observations of the ground-state transition of o-H2D+ were analysed in a large sample of high-mass clumps selected from the ATLASGAL survey at different evolutionary stages. Column densities and beam-averaged abundances of o-H2D+ with respect to H2, X(o-H2D+), were obtained by modelling the spectra under the assumption of local thermodynamic equilibrium. Results. We detect 16 sources in o-H2D+ and find clear correlations between X(o-H2D+) and the clump bolometric luminosity and the dust temperature, while only a mild correlation is found with the CO-depletion factor. In addition, we see a clear correlation with the luminosity-to-mass ratio, which is known to trace the evolution of the star formation process. This would indicate that the deuterated forms of H3+ are more abundant in the very early stages of the star formation process and that deuteration is influenced by the time evolution of the clumps. In this respect, our findings would suggest that the X(o-H2D+) abundance is mainly affected by the thermal changes rather than density changes in the gas. We have employed these findings together with observations of H13CO+, DCO+, and C17O to provide an estimate of the cosmic-ray ionisation rate in a sub-sample of eight clumps based on recent analytical work. Conclusions. Our study presents the largest sample of o-H2D+ in star-forming regions to date. The results confirm that the deuteration process is strongly affected by temperature and suggests that o-H2D+ can be considered a reliable chemical clock during the star formation processes, as proved by its strong temporal dependence.

scholarly journals Analysis of geomagnetic storm variations and count-rate of cosmic ray muons recorded at the Brazilian southern space observatory

2007 ◽  
Vol 25 ◽  
pp. 159-162
Author(s):  
Everton Frigo ◽  
Jairo Francisco Savian ◽  
Marlos Rockenbach da Silva ◽  
Alisson Dal Lago ◽  
Nalin Babulal Trivedi ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
Count Rate ◽  
Cosmic Ray ◽  
Space Observatory

STUDY OF FORBUSH DECREASE EVENT AND ASSOCIATED GEOMAGNETIC FIELD AND COSMIC RAY INTENSITY VARIATION

2005 ◽  
Vol 20 (29) ◽  
pp. 6717-6719 ◽  
Author(s):  
S. K. MISHRA ◽  
D. P. TIWARI ◽  
S. C. KAUSHIK
Keyword(s):  
Forbush Decrease ◽  
Intensity Variation ◽  
Cosmic Ray ◽  
Strong Relationship ◽  
Geomagnetic Disturbances ◽  
Slow Recovery ◽  
Short Term ◽  
Cosmic Ray Intensity ◽  
Transient Disturbances ◽  
Term Basis

Transient decrease in cosmic ray intensity following by a slow recovery typically lasting for several days is identified as Forbush decrease (Fd) event. As a result the geomagnetic index (Dst) decreased up to 300 nT, indicating a large geomagnetic storm and the percentage Fd decrease has gone to 16% giving rise a cosmic ray storm. Both events coincided with interplanetary conditions. Therefore, a systematic study has been performed to investigate the variation of cosmic ray intensity along with the interplanetary and geomagnetic disturbances. Results indicate a strong relationship between geomagnetic activity and Forbush decrease on short-term basis. Two types of interplanetary transient disturbances, namely magnetic cloud events and bidirectional events are analyzed to study the short-term changes in the solar wind (SW) plasma components as well as in cosmic ray intensity.

scholarly journals ESTIMASI BADAI GEOMAGNET BERDASARKAN PERILAKU PARAMETER ANGIN SURYA DAN MEDAN MAGNET ANTARPLANET SEBELUM BADAI GEOMAGNET (THE ESTIMATION OF GEOMAGNETIC STORM BASED ON SOLAR WIND PARAMETERS AND INTERPLANETARY MAGNETIC FIELD BEHAVIOR BEFORE GEOMAGNETIC STOR

2017 ◽  
Vol 14 (2) ◽  
pp. 17
Author(s):  
Anwar Santoso ◽  
Mamat Rahimat ◽  
Rasdewita Kesumaningrum ◽  
Siska Filawati
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Geomagnetic Storm ◽  
Space Weather ◽  
Geomagnetic Storms ◽  
Storm Events ◽  
Science Center ◽  
Solar Wind Parameters ◽  
The Impact ◽  
The Imf

Space weather research is the principal activity at the Space Science Center, Lapan to learn characteristics and generator source of the space weather so that can mitigate its the impact on the Earth's environment as mandated in Law No. 21 Year 2013. One of them is the phenomenon of geomagnetic storms. Geomagnetic storms caused by the entry of solar wind together with the IMF Bz that leads to the south. The behavior of the solar wind parameters together with the IMF Bz before geomagnetic storms can determine the formation of geomagnetic storms that caused it. In spite that, by the solar wind parameters and IMF Bz behavior before geomagnetic storm can be estimated its intensity through the equation Dst * = 1.599 * Ptotal - 34.48. The result of this equation is obtained that the Dst minimum deviation between the raw data and the output of this equation to the geomagnetic storm events on March 17, 2013 is about of -2.51 nT or 1.9% and on the geomagnetic storm events on February 19, 2014 is about of 2.77 nT or 2, 5%. Thus, the equation Dst * = 1.599 * Ptotal - 34.48 is very good for the estimation of geomagnetic storms.

scholarly journals Precursory signals of Forbush decreases with and without shock wave

2021 ◽  
pp. 57-63
Author(s):  
Dimitra Lingri ◽  
Helen Mavromichalaki ◽  
Anatoly V. Belov ◽  
Eugenia A. Eroshenko
Keyword(s):  
Magnetic Field ◽  
Shock Wave ◽  
Interplanetary Magnetic Field ◽  
Selection Criteria ◽  
Forbush Decrease ◽  
Cosmic Ray ◽  
Abrupt Increase ◽  
Cosmic Ray Intensity ◽  
Similarities And Differences ◽  
Solar Disturbances

Many previous studies have shown that before the beginning of a Forbush Decrease (FD) of the cosmic ray intensity, a precursor signal can be observed. All these surveys were focused on FDs that are associated with a sudden storm com- mencement (SSC). In this work we demonstrate that precursors could also be observed in events without a SSC that is determined by an abrupt increase of the interplanetary magnetic field. The type of precursory signals and their diversity among the events are the main purpose of this study. We try to figure out similarities and differences on the signals and the associated events from both categories in the last fifty years, from 1969 to 2019, using the same selection criteria of the under investigation FDs. Simultaneously the orientation of the upcoming solar disturbances in comparison to the way they configure the increase of the interplanetary magnetic field and create these signals are discussed.

The effect of Forbush decreases on the polar-night HOx concentration

2021 ◽  
Author(s):  
Irina Mironova
Keyword(s):  
Forbush Decrease ◽  
Cosmic Ray ◽  
Solar Proton ◽  
Polar Night ◽  
Forbush Decreases ◽  
Ozone Loss ◽  
Solar Proton Events ◽  
Hydrogen Oxide ◽  
The Impact ◽  
Ionization Rates

<div> <div> <div> <p>It is well-known that energetic particle precipitations during solar proton events increase ionization rates in the middle atmosphere enhancing the production of hydrogen oxide radicals (HOx) involved in the catalytic ozone destruction cycle. There are many studies where the contribution of energetic particles to the formation of hydrogen oxide radicals and ozone loss has been widely investigated. However, until now, there was no solid evidence that the reduction in galactic cosmic ray fluxes during a magnetic storm, known as Forbush-effect, directly and noticeably affects the polar-night stratospheric chemistry.<br>Here, the impact of the Forbush decrease on the behaviour of hydrogen oxide radicals was explored using the chemistry-climate model SOCOL.<br>We found that hydrogen oxide radical lost about half of its concentration over the polar boreal night stratosphere owing to a reduction in ionization rates caused by Forbush decreases after solar proton events occurred on 17 and 20 of January 2005. A robust response in ozone was not found. There is not any statistically significant response in (NOx) on Forbush decrease events as well as over summertime in the southern polar region.<br>The results of this study can be used to increase the veracity of ozone loss estimation if stronger Forbush events can have a place.</p> <p>Reference: Mironova I, Karagodin-Doyennel A and Rozanov E (2021) , The effect of Forbush decreases on the polar-night HOx concentration affecting stratospheric ozone. Front. Earth Sci. 8:618583. doi: 10.3389/feart.2020.618583</p> <p>https://www.frontiersin.org/articles/10.3389/feart.2020.618583/full</p> <p>The study was supported by the Russian Science Foundation grant (RSF project No. 20-67-46016).</p> </div> </div> </div>

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