S. I. Svertilov

Solar and Heliospheric Phenomena in October-November 2003: Causes and Effects

We present new observational data on the phenomena of extremely high activity on the Sun and in the heliosphere that took place in October–November 2003. A large variety of solar and heliospheric parameters give evidence that the interval under consideration is unique over the entire observation time. Based on these data, comparing them with similar situations in the past and using available theoretical concepts, we discuss possible cause-and-effect connections between the processes observed. The paper includes the first results and conclusions derived by the collaboration “Solar Extreme Events-2003” organized in Russia for detailed investigations of these events. As a result of our consideration, it is beyond question that the physical causes of solar and heliospheric phenomena in October–November 2003 are not exclusively local and do not belong only to the active regions and solar atmosphere above them. The energy reservoirs and driving forces of these processes have a more global nature. In general, they are hidden from an observer, since ultimately their sources lie in the subphotospheric layers of the Sun, where changes that are fast and difficult to predict can sometimes take place (and indeed they do). Solar flares can serve as sufficiently good tracers of these sudden changes and reconstructions on the Sun, although one can still find other diagnostic indicators among the parameters of magnetic fields, motions of matter, and emission characteristics.

Polarization, Temporal, and Spectral Parameters of Solar Flare Hard X-rays as Measured by the SPR-N Instrument Onboard the CORONAS-F Satellite

The SPR-N polarimeter onboard the CORONAS-F satellite allows the X-ray polarization degree to be measured in energy ranges of 20–40, 40–60, and 60–100 keV. To measure the polarization, the method based on the Thompson scattering of solar X-ray photons in beryllium plates was used; the scattered photons were detected with a system of six CsI(Na) scintillation sensors. During the observation period from August 2001 to January 2005, the SPR-N instrument detected the hard X-rays of more than 90 solar flares. The October 29, 2003, event showed a significant polarization degree exceeding 70% in channels of E = 40–60 and 60–100 keV and about 50% in the 20-to 40-keV channel. The time profile of the polarization degree and the projection of the polarization plane onto the solar disk were determined. For 25 events, the upper limits of the part of polarized X-rays were estimated at 8 to 40%. For all the flares detected, time profiles (with a resolution of up to 4 s), hard X-ray radiation fluxes, and spectral index estimates were obtained.

Slewing Mirror Telescope optics for the early observation of UV/optical photons from Gamma-Ray Bursts

We report on design, manufacture, and testing of a Slewing Mirror Telescope (SMT), the first of its kind and a part of Ultra-Fast Flash Observatory-pathfinder (UFFO-p) for space-based prompt measurement of early UV/optical light curves from Gamma-Ray Bursts (GRBs). Using a fast slewing mirror of 150 mm diameter mounted on a 2 axis gimbal stage, SMT can deliver the images of GRB optical counterparts to the intensified CCD detector within 1.5~1.8 s over ± 35 degrees in the slewing field of view. Its Ritchey-Chrétien telescope of 100 mm diameter provides a 17 × 17 arcmin² instantaneous field of view. Technical details of design, construction, the laboratory performance tests in space environments for this unique SMT are described in conjunction with the plan for in-orbit operation onboard the Lomonosov satellite in 2013.

Vacuum nonlinear electrodynamics curvature of photon trajectories in pulsars and magnetars

The possibilities of observing some nonlinear electrodynamic effects, which can be manifested in hard emission of X-ray, gamma ray pulsars and magnetars by X-ray and gamma ray astronomy methods are discussed. The angular resolution and sensitivity of modern space observatories give the opportunity to study the nonlinear electrodynamic effects, which can occur in very strong magnetic fields of pulsars (

Peculiarities of intrinsic background in LaBr3: Ce and CeBr3 scintillating crystals

B\sim 10^{12}

Invariant spectral characteristics of the decay phases of energetic electron intensities in solar energetic particle events

G) and magnetars (

Nonlinear electrodynamic effect of ray bending in the magnetic-dipole field

B\sim 10^{15}

Nonlinear Electrodynamic Delay of Electromagnetic Signals in a Coulomb Field

G). Such magnetic field magnitudes are comparable with the typical value of magnetic field induction necessary for manifestation of electrodynamics non-linearity in vacuum. Thus, near a magneticneutron star the electromagnetic emission should undergo nonlinear electrodynamic effects in strong magnetic fields (such as bending of rays, fluxes dispersing, changing of spectra and polarization states). Manifestations of these effects in detected hard emission from magnetic neutron stars are discussed on the base of nonlinear generalizations of the Maxwell equation in vacuum. The dispersion equations for electromagnetic waves propagating in the magnetic dipole field were obtained in the framework of these theories.The possibility of observing the bending of a ray and gamma ray flux dispersing in the neutron star magnetic field are analyzed. The only nonlinear electrodynamicseffect, which can be measured principally, is the effect of gamma ray flux dispersion by the neutron star magnetic field. Studying this effect we can also obtain information on the nonlinear electrodynamics bending of a ray in the source. The main qualitative difference in predictions of different nonlinear electrodynamics theories are discussed.Near a magnetic neutron star electromagnetic emission should undergo nonlinear electrodynamic effects in strong magnetic fields. Manifestations of this effect in detected hard emission from magnetic neutron stars are discussed on the base of nonlinear generalizations of the Maxwell equation in vacuum. The dispersion equations for electromagnetic waves propagating in the magnetic dipole field were obtained in the framework of these theories.

Dynamics and Energetics of the Thermal and Nonthermal Components in the Solar Flare of January 20, 2005, Based on Data from Hard Electromagnetic Radiation Detectors Onboard the CORONAS-F Satellite

The intrinsic background was measured in LaBr3:Ce and CeBr3 scintillating crystals grown at the Institute of Solid-State Physics of the Russian Academy of Sciences. The measurements were taken in the range of γ-ray energies from 20 keV to ∼5 MeV. Cylindrical samples with dimensions of Ø 1.5 × 1.8 cm for LaBr3:Ce and Ø 0.5 × 1.5 cm for CeBr3 were used. Well-known peculiarities due to the 138La radioactive iso-tope and actinide contaminants were reproduced in the recorded background spectrum of the LaBr3:Ce crystal. The detailed spectrum of the intrinsic background in the CeBr3 crystal was measured for the first time. At energies of >200 keV, the background rate of CeBr3 appeared to be much lower than that of LaBr3:Ce both in the continuum and in the peculiarities associated with the radioactivity of possible contaminants.

Experiment on the Vernov satellite: Transient energetic processes in the Earth’s atmosphere and magnetosphere. Part I: Description of the experiment

Abstract Using simultaneous observations from two Helios s/c, we examined the intensity-time profiles of E > 0.3 MeV electrons during the decay phases of 20 gradual solar energetic particle (SEP) events. As previously found for the SEP event ions, the electron spectra and decay times were nearly invariant over large spatial regions in most events.