Some features of the sources of relativistic particles at the Sun in the solar cycles 21–23

Vashenyuk, É. V.; Balabin, Yu. V.; Pérez‐Peraza, J.; Gallegos-Cruz, A.; Miroshnichenko, L. I.

doi:10.1016/j.asr.2005.05.012

Cited by 87 publications

(83 citation statements)

References 16 publications

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“…A detailed description of the method is given elsewhere (Mishev, Kocharov, and Usoskin, 2014). The method is similar to that used by Shea and Smart (1982); Humble et al (1991); Cramp et al (1997); Bombardieri et al (2006); Vashenyuk et al (2006bVashenyuk et al ( , 2008.…”

Section: Modelling the Neutron Monitor Responsementioning

confidence: 99%

“…The strongest NM increases were observed at the South Pole (58.3 %) and SANAE (54.4 %) compared to pre-increase levels. In general the event was characterized by a large anisotropy in its initial phase (Bieber et al, 2002;Bombardieri et al, 2006;Vashenyuk et al, 2006b). An illustration of several computed asymptotic cones used for our analysis is shown in Figure 2.…”

Section: The Bastille Day Gle 59 On 14 July 2000mentioning

confidence: 99%

“…This is particularly important for GLEs, which possess an essential anisotropic part, specifically during the event's onset (Debrunner et al, 1988;Shea and Smart, 1990;Vashenyuk et al, 2006b;Bütikofer et al, 2009). Therefore, measurements performed by the worldwide network of NMs form the basis to assess the spectral and angular characteristics of SEPs near Earth.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of the Ground-Level Enhancements on 14 July 2000 and 13 December 2006 Using Neutron Monitor Data

Mishev

Usoskin

2016

Sol Phys

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On the basis of neutron monitor data we estimate the energy spectrum, anisotropy axis direction and pitch-angle distribution of solar energetic particles during two major ground level enhancements (GLE 59 on 14 July 2000 and GLE 70 on 13 December 2006). For the analysis we use a newly computed neutron monitor yield function. The method consists of several consecutive steps: definition of the asymptotic viewing cones of neutron monitor stations considered for the data analysis by computations of cosmic ray particles propagation in a model magnetosphere with the MAGNETOCOSMICS code; computation of the neutron monitor model responses and derivation of the solar energetic particle characteristics on the basis of inverse problem solution. The pitch-angle distribution and rigidity spectrum of highenergy protons are obtained as function of time in the course of ground level enhancements. A comparison with previously reported results is performed and reasonable agreement is achieved. A discussion of the obtained results is included as well their possible application is included.

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Section: Modelling the Neutron Monitor Responsementioning

confidence: 99%

Section: The Bastille Day Gle 59 On 14 July 2000mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Analysis of the Ground-Level Enhancements on 14 July 2000 and 13 December 2006 Using Neutron Monitor Data

Mishev

Usoskin

2016

Sol Phys

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“…The detailed description of the method is given elsewhere [15]. The method is similar to that used by [10,11]. The relative count rate increase of a given NM is expressed as:…”

Section: Methods For Derivation Of Strong Seps Spectra and Angular Chamentioning

confidence: 99%

“…Different methods and instruments have been used to study GLEs events, specifically based on NMs [8,9,10,11]. The worldwide NM network [12], is used as a giant spectrometer [13].…”

Section: Introductionmentioning

confidence: 99%

Using global neutron monitor network data for GLE analysis: recent results

Mishev¹,

Usoskin²,

Kocharov³

2017

Proceedings of 35th International Cosmic Ray Conference — PoS(ICRC2017)

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The solar cycle 23 provided several strong ground level enhancements (GLEs). The first strong GLE event of the cycle was observed on 14 July 2000 (the Bastille day event), while the last was observed on 13 December 2006. In addition, the period of late October -early November 2003 was characterized by strong cosmic ray variability and sequence of three GLEs. Cycle 23 produced also the second largest event in the observational history -20 January 2005 event. Here we perform a precise analysis of spectral and angular characteristics of solar energetic particle (SEP) events on the basis of neutron monitor (NM) data. We model particle propagation in the Earth's magnetosphere and atmosphere using a newly computed NM yield function at several altitudes above the sea level. The method includes several consecutive steps: detailed computation of asymptotic cones and rigidity cut-off of each NM station used in the analysis, making an initial guess of the inverse problem by assuming the apparent source position location in a convenient way, application of the NM yield function for detector response modelling and subsequent optimization procedure in order to derive spectral and angular characteristics of SEPs. Here, we present results from analysis of several GLEs. The SEP spectra and pitch angle distributions were obtained in their dynamical development throughout the events. We briefly demonstrate the capability of the method to assess SEP features of sub-GLE events, the details reported in this volum.Several case examples are discussed.

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Analysis of the ground level enhancement on 17 May 2012 using data from the global neutron monitor network

2014

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We have analyzed the data of the world neutron monitor network for the first ground level enhancement of solar cycle 24, the ground level enhancement (GLE) on 17 May 2012. A newly computed neutron monitor yield function and an inverse method are applied to estimate the energy spectrum, anisotropy axis direction, and pitch angle distribution of the high‐energy solar particles in interplanetary space. The method includes the determination of the asymptotic viewing cones of neutron monitor stations through computations of trajectories of cosmic rays in a model magnetosphere. The cosmic ray particle trajectories are determined with the GEANT‐based MAGNETOCOSMICS code using Tsyganenko 1989 and International Geomagnetic Reference Field models. Subsequent calculation of the neutron monitor responses with the model function is carried out, that represents an initial guess of the inverse problem. Derivation of the solar energetic particle characteristics is fulfilled by fitting the data of the global neutron monitor network using the Levenberg‐Marquardt method over the nine‐dimensional parameter space. The pitch angle distribution and rigidity spectrum of high‐energy protons are obtained as function of time in the course of the GLE. The angular distribution appears quite complicated. It comprises a focused beam along the interplanetary magnetic field line from the Sun and a loss‐cone feature around the opposite direction, possibly indicative of the particle transport in interplanetary magnetic field structures associated with previous coronal mass ejections.

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Some features of the sources of relativistic particles at the Sun in the solar cycles 21–23

Cited by 87 publications

References 16 publications

Analysis of the Ground-Level Enhancements on 14 July 2000 and 13 December 2006 Using Neutron Monitor Data

Analysis of the Ground-Level Enhancements on 14 July 2000 and 13 December 2006 Using Neutron Monitor Data

Using global neutron monitor network data for GLE analysis: recent results

Analysis of the ground level enhancement on 17 May 2012 using data from the global neutron monitor network

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