Cosmic rays and stochastic magnetic reconnection in the heliotail

Desiati, P.; Lazarían, A.

doi:10.5194/npg-19-351-2012

Cited by 17 publications

(17 citation statements)

References 74 publications

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“…Each region is approximately 200-300 AU wide, roughly the proton gyroradius at TeV energies in typical Galactic magnetic fields. Cosmic rays, especially with high Z, might be affected by these magnetized regions, in particular those produced in the previous solar cycle and just past the solar system toward the heliotail (Lazarian & Desiati 2010;Desiati & Lazarian 2012, 2013. We should observe an 11-year modulation, although not necessarily in sync with the current solar cycle.…”

Section: Time Dependencementioning

confidence: 99%

Anisotropy in Cosmic-Ray Arrival Directions in the Southern Hemisphere Based on Six Years of Data From the Icecube Detector

Aartsen

Abraham

Ackermann³

et al. 2016

ApJ

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The IceCube Neutrino Observatory accumulated a total of 318 billion cosmic-ray-induced muon events between 2009 May and 2015 May. This data set was used for a detailed analysis of the sidereal anisotropy in the arrival directions of cosmic rays in the TeV to PeV energy range. The observed global sidereal anisotropy features large regions of relative excess and deficit, with amplitudes of the order of 10 −3 up to about 100 TeV. A decomposition of the arrival direction distribution into spherical harmonics shows that most of the power is contained in the lowmultipole (ℓ4) moments. However, higher multipole components are found to be statistically significant down to an angular scale of less than 10°, approaching the angular resolution of the detector. Above 100 TeV, a change in the morphology of the arrival direction distribution is observed, and the anisotropy is characterized by a wide relative deficit whose amplitude increases with primary energy up to at least 5 PeV, the highest energies currently accessible to IceCube. No time dependence of the large-and small-scale structures is observed in the period of six years covered by this analysis. The high-statistics data set reveals more details of the properties of the anisotropy and is potentially able to shed light on the various physical processes that are responsible for the complex angular structure and energy evolution.

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Section: Time Dependencementioning

confidence: 99%

Anisotropy in Cosmic-Ray Arrival Directions in the Southern Hemisphere Based on Six Years of Data From the Icecube Detector

Aartsen

Abraham

Ackermann³

et al. 2016

ApJ

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“…The experimental determination of small angular scale anisotropy is generally performed by filtering out the largescale modulations from the observed arrival direction distribution, thus retaining all structures with large angular gradients. Some of the small-scale anisotropy features seem to be correlated to regions in the sky where the global anisotropy has large variations (see Desiati & Lazarian 2013) or may be an effect of re-acceleration by magnetic reconnection processes in the tail of the heliosphere (Lazarian & Desiati 2010;Desiati & Lazarian 2012). However, globally, the observed small-scale anisotropy may appear to be rather randomly structured and, therefore, possibly a natural consequence of cosmic-ray propagation in the local turbulent magnetic field in the presence of a global anisotropy (Giacinti & Sigl 2012).…”

Section: Introductionmentioning

confidence: 99%

Cosmic-Ray Small-Scale Anisotropies and Local Turbulent Magnetic Fields

López-Barquero

Farber

Desiati

et al. 2016

ApJ

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Cosmic-ray anisotropy has been observed in a wide energy range and at different angular scales by a variety of experiments over the past decade. However, no comprehensive or satisfactory explanation has been put forth to date. The arrival distribution of cosmicrays at Earth is the convolution of the distribution of their sources and of the effects of geometry and properties of the magnetic field through which particles propagate. It is generally believed that the anisotropy topology at the largest angular scale is adiabatically shaped by diffusion in the structured interstellar magnetic field. On the contrary, the medium-and small-scale angular structure could be an effect of nondiffusive propagation of cosmicrays in perturbed magnetic fields. In particular, a possible explanation forthe observed small-scale anisotropy observed at theTeV energy scalemay be the effect of particle propagation in turbulent magnetized plasmas. We perform numerical integration of test particle trajectories in low-β compressible magnetohydrodynamic turbulence to study how the cosmicrays' arrival direction distribution is perturbed when they stream along the local turbulent magnetic field. We utilize Liouville's theorem for obtaining the anisotropy at Earth and provide the theoretical framework for the application of the theorem in the specific case of cosmic-ray arrival distribution. In this work, we discuss the effects on the anisotropy arising from propagation in this inhomogeneous and turbulent interstellar magnetic field.

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“…If confirmed, such observations might indicate that the small fraction of cosmic rays from this narrow angular region might be reaccelerated in magnetic reconnection processes occurring in between the unipolar magnetic domains generated by solar cycles (Lazarian and Desiati, 2010;Desiati and Lazarian, 2012). Such reacceleration processes would only involve a negligible fraction of the total turbulent energy transported by the solar wind across the heliotail.…”

Section: Heliospheric Influence On Tev Cosmic Raysmentioning

confidence: 83%

TeV Cosmic Ray Anisotropy and the Heliospheric Magnetic Field

Desiati

Lazarían

2014

ASTRA Proc.

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Abstract. Cosmic rays are observed to possess a small non uniform distribution in arrival direction. Such anisotropy appears to have a roughly consistent topology between tens of GeV and hundreds of TeV, with a smooth energy dependency on phase and amplitude. Above a few hundreds of TeV a sudden change in the topology of the anisotropy is observed. The distribution of cosmic ray sources in the Milky Way is expected to inject anisotropy on the cosmic ray flux. The nearest and most recent sources, in particular, are expected to contribute more significantly than others. Moreover the interstellar medium is expected to have different characteristics throughout the Galaxy, with different turbulent properties and injection scales. Propagation effects in the interstellar magnetic field can shape the cosmic ray particle distribution as well. In particular, in the 1-10 TeV energy range, they have a gyroradius comparable to the size of the Heliosphere, assuming a typical interstellar magnetic field strength of 3 µG. Therefore they are expected to be strongly affected by the Heliosphere in a manner ordered by the direction of the local interstellar magnetic field and of the heliotail. In this paper we discuss on the possibility that TeV cosmic rays arrival distribution might be significantly redistributed as they propagate through the Heliosphere.

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Cosmic rays and stochastic magnetic reconnection in the heliotail

Cited by 17 publications

References 74 publications

Anisotropy in Cosmic-Ray Arrival Directions in the Southern Hemisphere Based on Six Years of Data From the Icecube Detector

Anisotropy in Cosmic-Ray Arrival Directions in the Southern Hemisphere Based on Six Years of Data From the Icecube Detector

Cosmic-Ray Small-Scale Anisotropies and Local Turbulent Magnetic Fields

TeV Cosmic Ray Anisotropy and the Heliospheric Magnetic Field

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