Jorge Alberto Perez-Peraza

Solar cosmic rays: 70 years of ground-based observations

The main data have been summarized, and the results, achieved using data from the worldwide network during the entire period of ground-based observations of solar cosmic rays (SCRs) from February 28, 1942, when they were discovered, have been generalized. The methods and equipment for registering SCRs have been described. The physical, methodical, and applied aspects, related to the SCR generation, as well as the SCR interaction with the solar atmosphere, transport in the IMF, motion in the Earth’s magnetosphere, and the affect on the Earth’s atmosphere, have been discussed. It has been indicated that the fundamental results were achieved in this field of space physics during 70 years of studies. Special attention has been paid to up-to-date models and concepts of ground-level enhancement (GLE). The most promising tendencies in the development and application of this effective method of solar-terrestrial physics have been outlined.

IMPULSIVE, STOCHASTIC, AND SHOCK WAVE ACCELERATION OF RELATIVISTIC PROTONS IN LARGE SOLAR EVENTS OF 1989 SEPTEMBER 29, 2000 JULY 14, 2003 OCTOBER 28, AND 2005 JANUARY 20

Using the data from neutron monitors and applying various techniques, the parameters of relativistic solar protons (RSPs) outside the magnetosphere are currently being derived by several research groups. Such data, together with direct proton measurements from balloons and spacecraft, allow the determination of particle energy spectra near the Earths orbit in successive moments of time. Spectra of RSPs in a number of large solar events tend to indicate the existence of multistep acceleration at/near the Sun. In this paper, we study the generation of RSP by neutral current sheet, stochastic, and shock-wave acceleration, within the framework of two-component concepts for ground level enhancements (GLEs) of solar cosmic rays (SCRs). Our analysis is extended to large solar events (GLEs) of 1989 September 29, 2000 July 14, 2003 October 28, and 2005 January 20. We found two different particle populations (components) in the relativistic energy range: a prompt component (PC), characterized by an early impulselike intensity increase, hard spectrum and high anisotropy, and a delayed component, presenting a gradual late increase, soft spectrum and low anisotropy. Based on a two-source model for SCR spectrum formation at the Sun, we carried out theoretical calculations of spectra in the sources for both components. We conclude that the processes in neutral current sheet, together with stochastic acceleration in expanding magnetic trap in the solar corona, are able to explain the production of two different relativistic components. Shock acceleration in the presence of coronal mass ejection (CME) fits fairly only the nonrelativistic range of the SCR spectrum, but fails in the description of relativistic proton spectra, especially for the PC.

On the formation of relativistic particle fluxes in extended coronal structures

We analyze neutron monitor data of solar cosmic rays in order to obtain information about their sources. We use three methods for these data analysis. As result, we obtain a set of evidences for two separate solar cosmic rays sources that we call as prompt and delayed components. We attempt here to substantiate a two sources scenario for the generation of both components. For the prompt component source, we suggest regular acceleration in a neutral current sheet. For the delayed one, we propose acceleration by magnetosonic wave turbulence.

Particle charge evolution during acceleration processes in solar flares

It has been customary to assume that the charge state of energetic particles corresponds to the ionization equilibrium of the ambient plasma within the acceleration region. Nonetheless, we ascribe to a different opinion, by suggesting that charge interchange mechanisms may be activated during the ensuing acceleration process. We substantiate our claim by the calculated behaviour of charge states corresponding to energized ions while they are accelerated in the source regions. These computations are based on the electron capture and loss cross sections. Results from the analysis allow us to conclude that, contrary to the general assumption, charge exchange processes may be invoked during the acceleration of energized ions in solar flares.

Search for periodicities in galactic cosmic rays, sunspots and coronal index before arrival of relativistic protons from the sun

Using different approaches and techniques of wavelet analysis we analyze variations (oscillations) of galactic cosmic rays, solar spot number, and coronal index of solar activity before ground level enhancements of solar cosmic rays. Obtained results are discussed in frames of recent ideas about periodicity phenomena in the photosphere, and corona of the Sun, interplanetary medium, and cosmic rays.

Two-component concept for ground level enhancements of solar cosmic rays: Solar and interplanetary aspects

We discuss solar and interplanetary aspects concerning the observations and interpretation of two relativistic components of solar cosmic rays (SCRs), namely, impulsive (prompt) and slow (delayed) components (PC and DC, respectively). The prompt component is characterized by the strong anisotropy and exponential energy spectrum. The delayed component is essentially isotropic and has a power-law energy spectrum. Our analysis of observational data and theoretical arguments rules out the interplanetary propagation as the origin for these two components. Most likely, they are formed in the SCR generation on the Sun within the framework of two-source model with multiple acceleration processes in the solar atmosphere.

Electron-capture spectroscopy for identification of source ionization states and acceleration processes of SCR

Abstract It is illustrated how the radiation from electron-capture following the interaction of energetic ions, during their acceleration, with ions and atoms of the local matter is a very useful tool for diagnostics of cosmic and laboratory particle processes.

Parametrization of hadronic cross sections in the range 10−2–102 TeV

Present estimations of proton-proton total cross sections at very high energies are obtained from cosmic rays (>1017 eV): by means of some approximations, it is possible to get a value for the proton-proton total cross section from the knowledge of the proton-air cross section at these energies. Besides, total cross sections are measured with present day high energy colliders up to nearly 2 TeV in the center of mass (∼1015 eV in the lab.): several theoretical, empirical or semi-empirical parametrizations, very successful for interpolation at accelerator energies, can then be used to extrapolate the measured value to cosmic ray energies and get a reasonable estimation of cross sections at higher energies (∼1017 eV). Here we use a phenomenological model based on the Multiple-Diffraction approach to estimate proton-proton total cross sections at cosmic ray energies: on the basis of a forecasting regression analysis we determine confident error bands. We show that our predictions are highly sensitive to the e...

Prediction of σpptot at high energies with highly confident uncertainty band

Prediction procedures of significant physical quantities represent a useful tool in drawing inferences about the behavior of the out-of- the range data and so, about the generator events. Theoretical predictions out of the range of a data set involve a certain degree of uncertainty. With the aim of evaluating the confidence of such predictions it is convenient to determine the uncertainty associated to the predictions of the data. In the context of p-p cross sections at very high energies a great deal of work has been done out of the energy range of accelerators using different models (single-pomeron, dipole pomeron, multiple-diffraction, QCD and so on) to extrapolate accelerator data: predictions are usually compared to cosmic ray data producing a disagreement which explanation has also been widely discussed in the literature. We claim that such comparison requires of a highly confident band of uncertainty for any parametrization model. Here, we present a statistical method that allows to determine the r...