V. V. Borog

Investigating the energy, angular, and temporal characteristics of forbush effects registered by the URAGAN muon hodoscope

The results from analyzing variations in the flux of cosmic ray muons during Forbush effects (FEs) registered by the URAGAN muon hodoscope over the period 2005–2009 are presented. The dependences of the amplitudes for reductions in the intensity of the cosmic ray muon flux on the energy of primary particles in energy ranges higher than 10 GeV were obtained. Their changes upon different phases of Forbush effect development were investigated. The local anisotropy vectors were calculated on the basis of spatial-angular variations in the muon flux. Correlations between the parameters of physical properties in the near heloiosphere related to the Forbush effects and the characteristics of muon flux variations were analyzed.

Muon Diagnostics of the Earth's Atmosphere and Magnetosphere

A method of distant monitoring of the Earth’s magnetosphere and atmosphere is described, which is based on the close correlation between the modulations in the flux of atmospheric muons detected at the Earth’s surface and the dynamic processes in the Earth’s magnetosphere and atmosphere and implies the use of large-area muon hodoscopes with high angular accuracy of muon detection. The results of the analysis of the experimental data obtained on the muon hodoscopes used at the Moscow Engineering Physics Institute show that muon detection at the Earth’s surface in the hodoscopic mode gives a qualitatively new information about the main sources of muon flux modulation.

Present status of muon diagnostics

Muon diagnostics is a technique of remote monitoring of various dynamic processes in the heliosphere, the magnetosphere and the atmosphere of the Earth based on the analysis of spatial-angular and temporal variations of muon flux simultaneously detected from all directions of the upper hemisphere. The developed approaches to data analysis and results of the study of various terrestrial and extra-terrestrial processes detected by means of a wide aperture URAGAN muon hodoscope are discussed.

Study of characteristics of Forbush decreases detected in 2006 ? 2011 by means of muon hodoscope URAGAN

Results of the study of variations of cosmic ray muon flux at the Earth surface during Forbush decreases (FD) registered in 2006 – 2011 by means of muon hodoscope URAGAN both for the integral counting rate and for different angular intervals are presented. Dependences of the amplitude of the decrease of cosmic ray muon intensity on the energy of primary particles in the energy region above 10 GeV during different phases of the FD were obtained. On the basis of the analysis of spatial-angular distribution of muon flux, values of the horizontal projections of the local anisotropy vector were calculated and their dynamics was studied. Energy, angular and temporal characteristics of Forbush decreases determined from cosmic ray muon data are compared with basic parameters characterizing conditions of near-Earth space before and during FD.

Muon diagnostics: Present status

Muon diagnostics is a technique for the remote monitoring of various dynamic processes in the heliosphere and the Earth’s magnetosphere and atmosphere, based on analyzing spatial and angular variations in the flux of muons detected simultaneously from all directions in the upper hemisphere. Approaches to data analysis and some of the results of studies of the atmospheric and extra-atmospheric processes detected using the URAGAN muon hodoscope are discussed.

Flicker-noise spectroscopy of the muon flux during heliospheric disturbances

Flicker-noise spectroscopy (FNS) is used to identify high energy phenomena on the Sun and in the heliosphere. Such processes as the generation of solar cosmic rays (SCRs) or the eruption and propagation of coronal mass ejections (CMEs) in the heliosphere result in short-lived flux variations in both primary cosmic rays and secondary atmospheric muons. Flare and modulation effects at high energies are barely noticeable and are in most cases hidden in the statistical noise of the muon flux at ground level. Generalized FNS allows us to identify such processes. The identification of GLE event #70 is given as an example; this event of ground level enhancement (GLE) was recorded by the URAGAN muon hodoscope and a number of neutron monitors with high geomagnetic cutoffs. The developed technique can be used to analyze a wide range of different helio- and geophysical processes.

Investigation of geoeffective and non-geoeffective CMEs according to data from the URAGAN muon hodoscope

Coronal mass ejections are the brightest manifestations of solar activity. Dozens of coronal mass ejections are observed daily during periods of higher solar activity. They directly affect cosmic ray fluxes that carry information on plasma clouds, including clouds moving toward the Earth. Several aspects of geoeffective and non-geoeffective coronal mass ejections, observed with the ground-based URAGAN muon hodoscope operated as part of the NEVOD experimental complex at MEPhI, are discussed. The anisotropy of cosmic ray muon fluxes recorded during coronal mass ejections in 2014 and 2015 is investigated.

Characteristics of the Forbush decrease of 22 June 2015 measured by means of the muon hodoscope URAGAN

Results of the studies of cosmic ray muon flux variations during the powerful Forbush effect registered by the muon hodoscope URAGAN on June 22, 2015 are presented. From the muon flux angular distribution, the dependence of the intensity decrease amplitude on the primary particle energy in the region above 10 GeV has been obtained. The changes of this dependence at different phases of the Forbush effect development have been studied. Based on the analysis of spatial and angular variations of the muon flux, the values of the local anisotropy vector parameters, as well as unique muon snapshots (muonographies) have been obtained. The characteristics of the heliospheric and magnetospheric disturbances during the considered event have been analyzed.

Local anisotropy of muon flux during Forbush decreases from URAGAN data

The approach to the analysis of spatial-angular characteristics of the muon flux variations at different phases of Forbush decrease development according to the muon snapshots (muongraphies) obtained using muon hodoscope URAGAN, as well as the analysis results are presented.

Real-time experimental data of the muon hodoscope URAGAN accessible in www

Muon hodoscope URAGAN consists of four independent supermodules with total area 46 m2 and is under operation in the Experimental complex NEVOD (MEPhI, Moscow) from 2007. At present, the sequence of real-time data of angular variations of muon flux measured in the hodoscopic mode and also the results of their analysis: local angular anisotropy, wavelet frequencies, etc. are available at the URAGAN web-site. Some peculiarities of application of these data for the analysis of various events in heliosphere, magnetosphere and atmosphere are discussed.