scholarly journals Orographic effect in cosmic rays observing

2019 ◽  
Vol 127 ◽  
pp. 02020
Author(s):  
Yury Balabin
Keyword(s):  
Cosmic Rays ◽  
Sea Level ◽  
Cosmic Ray ◽  
Ground Level ◽  
Pressure Variation ◽  
Northern Caucasus ◽  
Local Conditions ◽  
Orographic Effect ◽  
Pressure Meter ◽  
Pressure Changes

The Baksan neutron monitor (NM) is installed at the Baksan neutrino observatory, the Northern Caucasus, which is located at the bottom of the Baksan gorge, at height of 1700 m above sea level. The cosmic rays flux recorded at the ground level depends on the amount of the substance (air), through which the particles are passing, from the uppermost layers of the atmosphere to a cosmic ray detector. So, besides the cosmic rays flux data, the station records pressure; the pressure meter recordings interval is 1 minute, like that of the cosmic rays. The perennial barometric data have been analysed to show that at the Baksan station one can often observe a daily pressure variation that is related to the topography features. In general, the local conditions (wind, local orographic effect) result in pressure variations, which do not occur in the cosmic rays, because they do not change the thickness of the atmosphere but result from the effect of the ground level. The barometric variation discovered is not so big (about 1 mb), but is also synchronously observed in the cosmic rays. It means that the pressure variation is not a local phenomenon. In this case, the NM detects the amount of the substance in the atmosphere, showing that pressure changes are not due to dynamic reasons (the Bernoulli effect) and it is the atmosphere strata that changes in reality. Hence, the orographic effect covers a significant part of the troposphere, resulting in the change of the atmosphere strata located over the NM. No similar pressure variation is observed in other NMs.

scholarly journals Short- and Medium-Term Induced Ionization in the Earth Atmosphere by Galactic and Solar Cosmic Rays

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Alexander Mishev
Keyword(s):  
Cosmic Rays ◽  
Cosmic Ray ◽  
Ground Level ◽  
Galactic Cosmic Rays ◽  
Earth Atmosphere ◽  
Medium Term ◽  
Ground Level Enhancement ◽  
Solar Cosmic Rays ◽  
The Earth ◽  
Ionization Effect

The galactic cosmic rays are the main source of ionization in the troposphere of the Earth. Solar energetic particles of MeV energies cause an excess of ionization in the atmosphere, specifically over polar caps. The ionization effect during the major ground level enhancement 69 on January 20, 2005 is studied at various time scales. The estimation of ion rate is based on a recent numerical model for cosmic-ray-induced ionization. The ionization effect in the Earth atmosphere is obtained on the basis of solar proton energy spectra, reconstructed from GOES 11 measurements and subsequent full Monte Carlo simulation of cosmic-ray-induced atmospheric cascade. The evolution of atmospheric cascade is performed with CORSIKA 6.990 code using FLUKA 2011 and QGSJET II hadron interaction models. The atmospheric ion rate is explicitly obtained for various latitudes, namely, 40°N, 60°N and 80°N. The time evolution of obtained ion rates is presented. The short- and medium-term ionization effect is compared with the average effect due to galactic cosmic rays. It is demonstrated that ionization effect is significant only in subpolar and polar atmosphere during the major ground level enhancement of January 20, 2005. It is negative in troposphere at midlatitude, because of the accompanying Forbush effect.

scholarly journals Cosmic Ray Evidence for the Magnetic Configuration of the Heliosphere

1981 ◽  
Vol 94 ◽  
pp. 397-398
Author(s):  
H. S. Ahluwalia
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
Ground Level ◽  
The Sun ◽  
Ground Level Enhancement ◽  
Solar Cosmic Rays ◽  
Pile Up ◽  
Scattered Component

Sekido and Murakami (1958) proposed the existence of the heliosphere to explain the scattered component of the solar cosmic rays. The heliosphere of their conception is a spherical shell around the sun. The shell contains a highly-irregular magnetic field and serves to scatter the cosmic rays emitted by the sun. It thereby gives rise to an isotropic component of solar cosmic rays, following the maximum in the ground level enhancement (GLE). Meyer et al. (1956) showed that a similar picture applies to the GLE of 23 February 1956. They conclude that the inner and outer radii of the shell should be 1.4 AU and 5 AU respectively. They suggest that a shell is formed by the “pile-up” of the solar wind under pressure exerted by the interstellar magnetic field, as suggested by Davis (1955).

Time and other Variations in the Intensity of Cosmic Ray Neutrons

1951 ◽  
Vol 6 (11) ◽  
pp. 592-598
Author(s):  
N. Adams ◽  
H. J. J. Braddick
Keyword(s):  
Cosmic Rays ◽  
Solar Flare ◽  
Diurnal Variation ◽  
Sea Level ◽  
Geomagnetic Latitude ◽  
Cosmic Ray ◽  
Temporal Variations ◽  
Neutron Production ◽  
Neutron Intensity

AbstractWe have measured the barometer coefficient of cosmic ray neutron production at sea level and find the value -9,25% ± 0,20/cmHg. We have shown that there is no diurnal variation of neutron production of amplitude greater than about 0,4 %. The effects of the large solar flare of November 19 th , 1949 on cosmic ray neutrons were much greater than on ionising cosmic rays at sea level; the maximum factor of increase was more than 5 and the intensity remained measurably above normal for about 12 hours. A small increase of neutron intensity is found, statistically, to be correlated with a number of recorded radio fade-outs. It is suggested that neutron measurements are particularly suitable for studying temporal variations of cosmic rays. The latitude increase of cosmic ray neutrons between geomagnetic latitude 54,5° and 56,5° was found to be about 2%. No certain increase was found between 56,5° and 59,5°.

scholarly journals Solar cosmic rays during the extremely high ground level enhancement on 23 February 1956

2005 ◽  
Vol 23 (6) ◽  
pp. 2281-2291 ◽  
Author(s):  
A. Belov ◽  
E. Eroshenko ◽  
H. Mavromichalaki ◽  
C. Plainaki ◽  
V. Yanke
Keyword(s):  
Cosmic Rays ◽  
Particle Density ◽  
Cosmic Ray ◽  
Ground Level ◽  
Particle Energy ◽  
Ground Level Enhancement ◽  
Solar Cosmic Rays ◽  
Solar Particle ◽  
Small Width ◽  
Standard Design

Abstract. The 23 February 1956 ground level enhancement of the solar cosmic ray intensity (GLE05) is the most famous among the proton events observed since 1942. But we do not have a great deal of information on this event due to the absence of solar wind and interplanetary magnetic field measurements at that time. Furthermore, there were no X-Ray or gamma observations and the information on the associated flare is limited. Cosmic ray data was obtained exclusively by ground level detectors of small size and in some cases of a non-standard design. In the present work all available data from neutron monitors operating in 1956 were analyzed, in order to develop a model of the solar cosmic ray behavior during the event. The time-dependent characteristics of the cosmic ray energy spectrum, cosmic ray anisotropy, and differential and integral fluxes have been evaluated utilizing different isotropic and anisotropic models. It is shown that the most outstanding features of this proton enhancement were a narrow and extremely intense beam of ultra-relativistic particles arriving at Earth just after the onset and the unusually high maximum solar particle energy. However, the contribution of this beam to the overall solar particle density and fluency was not significant because of its very short duration and small width. Our estimate of the integral flux for particles with energies over 100 MeV places this event above all subsequent. Perhaps the number of accelerated low energy particles was closer to a record value, but these particles passed mainly to the west of Earth. Many features of this GLE are apparently explained by the peculiarity of the particle interplanetary propagation from a remote (near the limb) source. The quality of the available neutron monitor data does not allow us to be certain of some details; these may be cleared up by the incorporation into the analysis of data from muonic telescopes and ionization chambers operating at that time. Keywords. Interplanatary physics (Cosmic rays; Energetic particles) – Solar physics, astrophysics and astronomy (Flares and mass injections)

scholarly journals Unusual decrease of the cosmic ray intensity in May 2019 on the background of the minima solar activity

2021 ◽  
pp. 73-80
Author(s):  
Liudmila Trefilova ◽  
Pavel G. Kobelev ◽  
Anatoly V. Belov ◽  
Eugenia A. Eroshenko ◽  
Anaid A. Melkumyan ◽  
...  
Keyword(s):  
Solar Activity ◽  
Cosmic Rays ◽  
Active Regions ◽  
Cosmic Ray ◽  
Ground Level ◽  
Neutron Monitors ◽  
Cosmic Ray Intensity ◽  
The Earth ◽  
24Th Cycle ◽  
Field Lines

In May 2019 there was a long and sloping decreasing of cosmic ray’s intensity (up to ~4%), which was observed on neutron monitors. Despite this was a small decreasing compared to quasi-eleven-period variation, it stands out well in 24th cycle of solar activity. According to LASCO/SOHO and STEREO-A data from spectrometer in different UHF bands and from coronograph, there was a series of CMEs which affected on modulation of cosmic rays by creating a series of Forbush decrea - sing, which didn’t restore. This series was connected to two active regions on sun and began on April 30 from “reversed halo” CME. This CME didn’t reach the earth, but led to significant additional modulation of cosmic rays, mostly on east side. Later there was a series of smaller CMEs on May 1-6, which also didn’t reach the earth, but were gradually approaching to Earth. Recent CMEs on 8-9 and 12-13 created a normal Forbush decreasing. In May 2019, cosmic rays shown again, that they can collect information about distant objects of geliosphere and transmit it to Earth. The ground-level detectors sometimes can observe an interaction of interplanetary distur- bances, which didn‘t reach the earth. East CMEs are especially effective, because they closing magnetic field lines beyond the orbit of earth and can interfere the restoring of cosmic ray’s intensity.

scholarly journals Measurement of Energy Spectrum and Elemental Composition of PeV Cosmic Rays: Open Problems and Prospects

2022 ◽  
Vol 12 (2) ◽  
pp. 705
Author(s):  
Giuseppe Di Sciascio
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
Ground Level ◽  
Galactic Cosmic Rays ◽  
Particle Energy ◽  
Open Problems ◽  
Indirect Measurements ◽  
Air Shower ◽  
Systematic Uncertainties

Cosmic rays represent one of the most important energy transformation processes of the universe. They bring information about the surrounding universe, our galaxy, and very probably also the extragalactic space, at least at the highest observed energies. More than one century after their discovery, we have no definitive models yet about the origin, acceleration and propagation processes of the radiation. The main reason is that there are still significant discrepancies among the results obtained by different experiments located at ground level, probably due to unknown systematic uncertainties affecting the measurements. In this document, we will focus on the detection of galactic cosmic rays from ground with air shower arrays up to 1018 eV. The aim of this paper is to discuss the conflicting results in the 1015 eV energy range and the perspectives to clarify the origin of the so-called `knee’ in the all-particle energy spectrum, crucial to give a solid basis for models up to the end of the cosmic ray spectrum. We will provide elements useful to understand the basic techniques used in reconstructing primary particle characteristics (energy, mass, and arrival direction) from the ground, and to show why indirect measurements are difficult and results are still conflicting.

Cosmic rays at ground level; a brief introduction

2021 ◽  
Author(s):  
Du Toit Strauss
Keyword(s):  
Cosmic Rays ◽  
Primary Particle ◽  
Secondary Particle ◽  
Cosmic Ray ◽  
Ground Level ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Neutron Monitors ◽  
The Earth

<p>Galactic cosmic rays, and sporadic high energy solar energetic particles, are energetic enough to pierce the Earth’s protective magnetosphere and interact with the atmosphere. Here, a secondary particle cascade leads to enhanced radiation levels which is of importance, for instance, to aviation dosimetry and related studies. At ground level, these secondary particles can be observed (indirectly) by means of neutron monitors, and this has been done for more than 70 years, providing a valuable long-term cosmic ray record. In this talk, we introduce the different primary particle populations, discuss their acceleration and modulation, and connect this with long-term neutron monitor measurements.</p>

The momentum spectrum of cosmic rays at a depth of 38 metres water equivalent underground

1959 ◽  
Vol 253 (1273) ◽  
pp. 163-176 ◽  
Keyword(s):  
Cosmic Rays ◽  
Energy Loss ◽  
Direct Determination ◽  
Cosmic Ray ◽  
Ground Level ◽  
Momentum Spectrum ◽  
Collision Process ◽  
Momentum Range ◽  
Level Spectrum

A direct determination has been made of the cosmic ray spectrum underground at a depth of 38 m. w. e. under Castle Rock, Nottingham. The spectrum is based on measurements of 1010 particles traversing a magnetic spectrograph having a maximum detectable momentum of 8 GeV/ c . By comparing this spectrum with the ground-level spectrum the energy loss of fast μ -mesons in penetrating the 38 m. w. e. of rock has been determined. It is shown that the energy loss for μ -mesons in the momentum range 7 to 15 GeV/ c is as expected by theory, the collision process being responsible for most of the loss.

Pressure variation in a fluid at rest (hydrostatics)

2018 ◽  
Author(s):  
Marcel Escudier
Keyword(s):  
Equation Of State ◽  
Static Pressure ◽  
Applied Pressure ◽  
Pressure Variation ◽  
Constant Density ◽  
Fluid Temperature ◽  
Earth’S Atmosphere ◽  
Hydrostatic Equation ◽  
Depth Increase ◽  
Pressure Changes

The three fundamental principles for the variation of static pressure p throughout a body of fluid at rest are (a) the pressure at a point is the same in all directions (Pascal’s law), (b) the pressure is the same at all points on the same horizontal level, and (c) the pressure increases with depth z according to the hydrostatic equation. dp/dz= ρ‎g For a fluid with constant density ρ‎, the increase in pressure over a depth increase h is ρ‎gh, a result which can be used to analyse the response of simple barometers and manometers to applied pressure changes and differences. In situations where very large changes in pressure occur an equation of state may be required to relate pressure and density together with an assumption about the fluid temperature. The hydrostatic equation is still valid but more difficult to integrate, as illustrated by consideration of the earth’s atmosphere.

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