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

scholarly journals Analysis of the Geomagnetic Storm Variations and the count-rate of Cosmic Ray Muons recorded at the Brazilian Southern Space Observatory

2005 ◽  
Author(s):  
Everton Frigo ◽  
Jairo F. Savian ◽  
Marlos R. da Silva ◽  
Alisson Dal Lago ◽  
Nalin B. Trivedi ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
Count Rate ◽  
Cosmic Ray ◽  
Space Observatory

scholarly journals Analysis of the Geomagnetic Storm Variations and the count-rate of Cosmic Ray Muons recorded at the Brazilian Southern Space Observatory

2005 ◽  
Author(s):  
Everton Frigo ◽  
Jairo F. Savian ◽  
Marlos R. da Silva ◽  
Alisson Dal Lago ◽  
Nalin B. Trivedi ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
Count Rate ◽  
Cosmic Ray ◽  
Space Observatory

Moisture and humidity dependence of the above-ground cosmic-ray neutron intensity revised

2021 ◽  
Author(s):  
Markus Köhli ◽  
Jannis Weimar ◽  
Benjamin Fersch ◽  
Roland Baatz ◽  
Martin Schrön ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Soil Moisture ◽  
Count Rate ◽  
Cosmic Ray ◽  
Mathematical Treatment ◽  
Specific Response ◽  
Parameter Equation ◽  
Neutron Count ◽  
Dry Conditions ◽  
Humidity Dependence

<p>The novel method of Cosmic-ray neutron sensing (CRNS) allows non-invasive soil moisture measurements at a hectometer scaled footprint. Up to now, the conversion of soil moisture to a detectable neutron count rate relies mainly on the equation presented by Desilets et al. (2010). While in general a hyperbolic expression can be derived from theoretical considerations, their empiric parameterisation needs to be revised for two reasons. Firstly, a rigorous mathematical treatment reveals that the values of the four parameters are ambiguous because their values are not independent. We find a 3-parameter equation with unambiguous values of the parameters which is equivalent in any other respect to the 4-parameter equation. Secondly, high-resolution Monte-Carlo simulations revealed a systematic deviation of the count rate to soil moisture relation especially for extremely dry conditions as well as very humid conditions. That is a hint, that a smaller contribution to the intensity was forgotten or not adequately treated by the conventional approach. Investigating the above-ground neutron flux by a broadly based Monte-Carlo simulation campaign revealed a more detailed understanding of different contributions to this signal, especially targeting air humidity corrections. The packages MCNP and URANOS were used to derive a function able to describe the respective dependencies including the effect of different hydrogen pools and the detector-specific response function. The new relationship has been tested at three exemplary measurement sites and its remarkable performance allows for a promising prospect of more comprehensive data quality in the future.</p>

scholarly journals Observing the neutron component during thunderstorm activity at a mountain CR station

2019 ◽  
Vol 5 (3) ◽  
pp. 54-58
Author(s):  
Анна Луковникова ◽  
Anna Lukovnikova ◽  
Виктор Алешков ◽  
Viktor Aleshkov ◽  
Алексей Лысак ◽  
...  
Keyword(s):  
Field Strength ◽  
Sea Level ◽  
Neutron Monitor ◽  
Electromagnetic Interference ◽  
Count Rate ◽  
Cosmic Ray ◽  
Thunderstorm Activity ◽  
Signal Discrimination ◽  
Lightning Discharges ◽  
Neutron Component

During three summer months in 2015, the Cosmic Ray (CR) station Irkutsk-3000, located at 3000 m above sea level, measured the CR neutron component intensity with the 6NM64 neutron monitor, as well as the atmospheric electric field strength and the level of electromagnetic interference during lightning discharges. It is shown that the level of electromagnetic interference, when registered during lightning discharges, depends considerably on the fixed level of signal discrimination. During observations, we observed no effects of thunderstorm discharges at the neutron monitor count rate at the CR station Irkutsk-3000.

scholarly journals The molecular gas in Luminous Infrared Galaxies: a new emergent picture

2012 ◽  
Vol 8 (S292) ◽  
pp. 209-214
Author(s):  
Padelis P. Papadopoulos ◽  
Zhi-Yu Zhang ◽  
Axel Weiss ◽  
Paul van der Werf ◽  
Kate Isaak ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Molecular Gas ◽  
Infrared Galaxies ◽  
Space Observatory ◽  
Local Universe ◽  
Star Forming ◽  
Luminous Infrared Galaxies ◽  
Physical Conditions ◽  
J 13 ◽  
Line Survey

AbstractResults from a large, multi-J CO, 13CO, and HCN line survey of Luminous Infrared Galaxies (LIRGs: LIR≥ 1010 L⊙) in the local Universe (z≤0.1), complemented by CO J=4–3 up to J=13–12 observations from the Herschel Space Observatory (HSO), paints a new picture for the average conditions of the molecular gas of the most luminous of these galaxies with turbulence and/or large cosmic ray (CR) energy densities UCR rather than far-UV/optical photons from star-forming sites as the dominant heating sources. Especially in ULIRGs (LIR>1012 L⊙) the Photon Dominated Regions (PDRs) can encompass at most a few % of their molecular gas mass while the large UCR∼ 103 UCR, Galaxy, and the strong turbulence in these merger/starbursts, can volumetrically heat much of their molecular gas to Tkin∼ (100-200) K, unhindered by the high dust extinctions. Moreover the strong supersonic turbulence in ULIRGs relocates much of their molecular gas at much higher average densities (≥104 cm−3) than in isolated spirals (∼ 102–103 cm−3). This renders low-J CO lines incapable of constraining the properties of the bulk of the molecular gas in ULIRGs, with substantial and systematic underestimates of its mass possible when only such lines are used. Finally a comparative study of multi-J HCN lines and CO SLEDs from J=1–0 up to J=13–12 of NGC 6240 and Arp 193 offers a clear example of two merger/starbursts whose similar low-J CO SLEDs, and LIR/LCO,1−0 and LHCN, 1−0/LCO,1-0 ratios (proxies of the so-called SF efficiency and dense gas mass fraction), yield no indications about their strongly diverging CO SLEDs beyond J=4–3, and ultimately the different physical conditions in their molecular ISM. The much larger sensitivity of ALMA and its excellent site in the Atacama desert now allows the observations necessary to assess the dominant energy sources of the molecular gas and its mass in LIRGs without depending on the low-J CO lines.

scholarly journals Soil Moisture and Air Humidity Dependence of the Above-Ground Cosmic-Ray Neutron Intensity

2021 ◽  
Vol 2 ◽  
Author(s):  
Markus Köhli ◽  
Jannis Weimar ◽  
Martin Schrön ◽  
Roland Baatz ◽  
Ulrich Schmidt
Keyword(s):  
Monte Carlo ◽  
Soil Moisture ◽  
Monte Carlo Simulations ◽  
Count Rate ◽  
Neutron Transport ◽  
Cosmic Ray ◽  
Mathematical Treatment ◽  
Specific Response ◽  
Air Humidity ◽  
Parameter Equation

Investigations of neutron transport through air and soil by Monte Carlo simulations led to major advancements toward a precise interpretation of measurements; they particularly improved the understanding of the cosmic-ray neutron footprint. Up to now, the conversion of soil moisture to a detectable neutron count rate has relied mainly on the equation presented by Desilets and Zreda in 2010. While in general a hyperbolic expression can be derived from theoretical considerations, their empiric parameterization needs to be revised for two reasons. Firstly, a rigorous mathematical treatment reveals that the values of the four parameters are ambiguous because their values are not independent. We found a three-parameter equation with unambiguous values of the parameters that is equivalent in any other respect to the four-parameter equation. Secondly, high-resolution Monte-Carlo simulations revealed a systematic deviation of the count rate to soil moisture relation especially for extremely dry conditions as well as very humid conditions. That is a hint that a smaller contribution to the intensity was forgotten or not adequately treated by the conventional approach. Investigating the above-ground neutron flux through a broadly based Monte-Carlo simulation campaign revealed a more detailed understanding of different contributions to this signal, especially targeting air humidity corrections. The packages MCNP and URANOS were used to derive a function able to describe the respective dependencies, including the effect of different hydrogen pools and the detector-specific response function. The new relationship has been tested at two exemplary measurement sites, and its remarkable performance allows for a promising prospect of more comprehensive data quality in the future.

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 An investigation into the correlation of geomagnetic storms with tropospheric parameters over the South Pole

2003 ◽  
Vol 21 (5) ◽  
pp. 1095-1100 ◽  
Author(s):  
M. M. Lam ◽  
A. S. Rodger
Keyword(s):  
Solar Wind ◽  
Geomagnetic Storm ◽  
Lower Stratosphere ◽  
Geomagnetic Storms ◽  
Cosmic Ray ◽  
Magnetic Activity ◽  
Atmospheric Composition ◽  
South Pole ◽  
The South ◽  
Interplanetary Physics

Abstract. We test the proposal that the Sun’s magnetic activity, communicated via the solar wind, provides a link between solar variability and the Earth’s climate in the Antarctic troposphere. The strength of a geomagnetic storm is one indicator of the state of the solar wind; therefore, we use the dates of 51 moderate to strong winter geomagnetic storms from the period 1961–1990 to conduct a series of superposed epoch analyses of the winter South Pole isobaric height and temperature, at pressures of between 100–500 mbar. Using Student’s t -test to compare the mean value of the pre- and post-storm data sets, we find no evidence to support the hypothesis that there is a statistically-significant correlation between the onset of a geomagnetic storm and changes in the isobaric temperature or height of the troposphere and lower stratosphere over the South Pole during winter months. This concurs with a similar study of the variability of the troposphere and lower stratosphere over the South Pole (Lam and Rodger, 2002) which uses drops in the level of observed galactic cosmic ray intensity, known as Forbush decreases, as a proxy for solar magnetic activity instead of geomagnetic storms.Key words. Interplanetary physics (solar wind plasma; cosmic rays) – Atmospheric composition and structure (pressure, density and temperature)

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