The 1990 May 24 solar cosmic-ray event

This paper presents an integrated analysis of GOES 6, 7 and neutron monitor observations of solar cosmic-ray event following the 1990 May 24 solar flare. We have used a model which includes particle injection at the Sun and at the interplanetary shock front and particle propagation through the interplanetary medium. The model does not attempt to simulate the physical processes of coronal transport and shock acceleration, therefore the injections at the Sun and at the shock are represented by source functions in the particle transport equation. By fitting anisotropy and angle-average intensity profiles of high-energy (>30 MeV) protons as derived from the model to the ones observed by neutron monitors and at GOES 6 and 7, we have determined the parameters of particle transport, the injection rate and spectrum at the source. We have made a direct fit of uncorrected GOES data with both primary and secondary proton channels taken into account.The 1990 May 24–26 energetic proton event had a double-peaked temporal structure at energies 100 MeV. The Moreton (shock) wave nearby the flare core was seen clearly before the first injection of accelerated particles into the interplanetary medium. Some (correlated with this shock) acceleration mechanism which operates in the solar corona at a height up to one solar radius is regarded as a source of the first (prompt) increase in GOES and neutron monitor counting rates. The proton injection spectrum during this increase is found to be hard (spectral index 1.6) at lower energies ( 30 MeV) with a rapid steepening above 300 MeV. Large values of the mean free path ( 1.8 AU for 1 GV protons in the vicinity of the Earth) led to a high anisotropy of arriving protons. The second (delayed) proton increase was presumably produced by acceleration/injection of particles by an interplanetary shock wave at height of 10 solar radii. Our analysis of the 1990 May 24–26 event is in favour of the general idea that a number of components of energetic particles may be produced while the flare process develops towards larger spatial/temporal scales.Visiting Associate from St. Petersburg State Technical University, St. Petersburg 195251, Russia.     

Multispacecraft observations of the east-west asymmetry of solar Energetic Storm Particle events

Multispacecraft observations of energetic protons (E _p 500 keV) were obtained by the APL/JHU instruments on board the IMP-7 and 8 spacecraft and the Voyager-1 and 2 deep space probes, in order to study the generation of solar flare Energetic Storm Particle (ESP) events at widely separated locations on the same shock front. These locations are presumably characterized, on the average, by different interplanetary magnetic field-shock front configurations, i.e. quasi-perpendicular (quasi-parallel) shocks for eastern (western) solar flare sites. The multispacecraft energetic proton observations show that substantial differences in the ESP proton intensity enhancements (defined as the ratio of intensity increases near the shock over the ambient solar proton population) are detected at these energies for locations on the shock front with wide heliolongitude separations. In particular, large ESP proton intensity enhancements are detected at locations on the shock front for which the solar flare site generating the shock is to the east of the spacecraft meridian, whereas only weak ESP events are observed at locations on the same shock for which the flare site is to the west of the spacecraft meridian. The results indicate that acceleration of ESP protons to E _p 500 keV takes place exclusively at the quasi-perpendicular shock front domain, consistent with the shock drift acceleration mechanism (Armstrong et al., 1977).     

On proton and electron acceleration by shock waves during large solar flares

The data on optical, X-ray and gamma emission from proton flares, as well as direct observations of flare-associated phenomena, show energetic proton acceleration in the corona rather than in the flare region. In the present paper, the acceleration of protons and accompanying relativistic electrons is accounted for by a shock wave arising during the development of a large flare. We deal with a regular acceleration mechanism due to multiple reflection of resonance protons and fast electrons from a collisionless shock wave front which serves as a moving mirror. The height of the most effective acceleration in the solar corona is determined. The accelerated particle energy and density are estimated. It is shown in particular that a transverse collisionless shock wave may produce the required flux of protons with energy of 10 MeV and of relativistic electrons of 1–10 MeV.The proposed scheme may also serve as an injection mechanism when the protons are accelerated up to relativistic energies by other methods.     

In situ acceleration and gradients of charged particles in the outer solar system observed by the voyager spacecraft

The probable connection between cosmic rays and the electromagnetic state of the interplanetary medium was recognized by Hannes Alfvén as early as 1949 (Alfvén, 1949, 1950); he pointed out that the properties of cosmic rays necessitate a mechanism, external to Earth but within the solar system, capable of accelerating particles to extremely high energies. In advocating the view of local origin for part of the cosmic-ray spectrum, Alfvén and his colleagues developed a very general type of acceleration mechanism called magnetic pumping. The unique data set of the two Voyagers extends over an entire decade (1977–1987) and is most suitable to explore the problem of acceleration of charged particles in the heliosphere. The energy coverage of the Low Energy Charged Particle (LECP) experiment covers the range 30 keV to several hundred MeV for ions and 22 keV to several MeV for electrons. Selected observations of interplanetary acceleration events from 1 to 25 AU are presented and reviewed. These show frequent acceleration of ions to several tens of MeV in association with shocks; highest energies (220 MeV oxygen) were measured in the near-perpendicular ( _Bn 87.5°) shock of January 5, 1978 at 1.9 AU, where electron acceleration was also observed. Examples of ion acceleration in association with corotating interaction regions are presented and discussed. It is shown that shock structures have profound effects on high-energy (70 MeV) cosmic rays, especially during solar minimum, when a negative latitudinal gradient was observed after early 1985 at all energies from 70 MeV down to 30 keV. By early 1987, most shock acceleration activity in the outer heliosphere (25 to 30 AU) had ceased both in the ecliptic (Voyager-2) and at higher (30°) ecliptic latitudes (Voyager-1). The totality of observations demonstrate that local acceleration to a few hundred MeV, and as high as a few GeV is continually present throughout the heliosphere. It should be noted that in 1954 when Alfvén suggested local acceleration and containment of cosmic rays within the solar system, no one treated his suggestion seriously, at any energy. The observations reviewed in this paper illustrate once more Alfvén's remarkable prescience and demonstrate how unwise it is to dismiss his ideas.Paper dedicated to Professor Hannes Alfvén on the occasion of his 80th birthday, 30 May 1988.     

Second-stage acceleration in a limb-occulted flare

We analyze hard and soft X-ray, microwave and meter wave radio, interplanetary particle, and optical data for the complex energetic solar event of 22 July 1972. The flare responsible for the observed phenomena most likely occurred 20° beyond the NW limb of the Sun, corresponding to an occultation height of 45 000 km. A group of type III radio bursts at meter wavelengths appeared to mark the impulsive phase of the flare, but no impulsive hard X-ray or microwave burst was observed. These impulsive-phase phenomena were apparently occulted by the solar disk as was the soft X-ray source that invariably accompanies an H flare. Nevertheless essentially all of the characteristic phenomena associated with second-stage acceleration in flares - type II radio burst, gradual second stage hard X-ray burst, meter wave flare continuum (FC II), extended microwave continuum, energetic electrons and ions in the interplanetary medium - were observed. The spectrum of the escaping electrons observed near Earth was approximately the same as that of the solar population and extended to well above 1 MeV.Our analysis of the data leads to the following results: (1) All characteristics are consistent with a hard X-ray source density n _i 10⁸ cm^–3 and magnetic field strength 10 G. (2) The second-stage acceleration was a physically distinct phenomenon which occurred for tens of minutes following the impulsive phase. (3) The acceleration occurred continuously throughout the event and was spatially widespread. (4) The accelerating agent was very likely the shock wave associated with the type II burst. (5) The emission mechanism for the meter-wave flare continuum source may have been plasma-wave conversion, rather than gyrosynchrotron emission.     

Magnetic-cloud chamber effects behind flare-generated shock waves

A mechanism explaining the generation of the helium-enriched plasma-condensation colud (HAE-events) behind the front of shock waves associated with mass-ejecting flares is presented. The mechanism is based on the occurence of physical conditions, analogous to those in a Wilson cloud chamber in a magnetic field, behind the front of a flare-generated shock wave propagation out into interplanetary space. Consequently, if the solar atmosphere above the flare active region is saturated with ejected helium plasma, conditions are created for the forming of the helium-enriched plasma-condensation colud in the temperature-depressed region behind the shock wave front.     

Shock wave effects in solar cosmic ray events

Two low-energy ( 1 MeV) solar proton events which display a gradual intensity increase to a maximum near the time of an SSC, followed by an abrupt, large decrease, are interpreted in terms of a population of cosmic rays which are swept ahead of an interplanetary shock wave. A model which describes the variation with time of intensity and anisotropy at the Earth is developed using a Monte Carlo technique which traces the histories of particles released impulsively at the Sun. A good fit to each of the profiles observed at 0.6 to 0.9 MeV proton energies is obtained with a diffusion coefficient 2 × 10²⁰ cm² s^–) = 13.46 - 2.99 sin²1 and a near perfect shock reflector.Now at University of California, LASL, Los Alamos, New Mexico.     

On the relation between solar-flare gamma-ray emission and proton escape into interplanetary space

It is shown that escaping of solar flare energetic protons into interplanetary space as well as their relation to the flare gamma-ray emission depend on the parameter = 8p/B ₀ ² , where p is the pressure of hot plasma and energetic particles and B ₀ is the magnetic field in a flaring loop. If 1, the bulk of the energetic protons escape to the loss cone because of diffusion due to small-scale Alfvén-wave turbulence, and precipitate into the footpoints of the flaring loop. The flare then produces intense gamma-ray line emission and a weak flux of high energy protons in interplanetary space. If >_*0.3-1.0, then fast eruption of hot plasma and energetic particles out of the flaring loop occurs, this being due to the flute instability or magnetic-field-plasma nonequilibrium. The flare then produces a comparatively weak gamma-radiation and rather intense proton fluxes in interplanetary space. We predict a modulation of the solar flare gamma-ray line emission with a period 1 s during the impulsive phase that is due to the MHD-oscillations of the energy release volume. The time lag of the gamma-ray peaks with respect to the hard X-ray peaks during a simultaneous acceleration of electrons and protons can be understood in terms of strong diffusion.     

Взаимооействие Излучения Рентгеновскооо Истооника с АтмосФерой Нормальной Звезды в Тесных Двойных Системах

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Energetic properties of interplanetary plasma at the earth's orbit following the August 4, 1972 flare

Solar wind and interplanetary magnetic field data were obtained by the PROGNOZ 1 and PROGNOZ 2 satellites during the period following the August 4, 1972 (0621 UT) solar flare. A thermalized plasma was recorded one hour after the shock followed two hours later by the plasma piston with a bulk velocity higher than 1700 km s^-1. The comparison between the PROGNOZ and PIONEER 9 solar wind data shows an attenuation of the plasma properties with the deflection from the flare's meridian.     

Prompt proton and electron acceleration to relativistic energies in solar flares

As a possible mechanism for particle acceleration in the impulsive phase of solar flares, a new particle acceleration mechanism in shock waves is proposed; a collisionless fast magnetosonic shock wave can promptly accelerate protons and electrons to relativistic energies, which was found by theory and relativistic particle simulation. The simultaneous acceleration of protons and electrons takes place in a rather strong magnetic field such that _{ce pe} . For a weak magnetic field ( _{ce pe} ), strong acceleration occurs to protons only. Resonant protons gain relativistic energies within the order of the ion cyclotron period (much less than 1 s for solar plasma parameters). The electron acceleration time is shorter than the ion-cyclotron period.     

Evidence for a two-component injection of cosmic rays from the solar flare of 1969, March 30

The solar flare of 1969 March 30, occurring 20° behind the west limb, produced very extensive 80 MHz radio emission at the Sun, and gave rise to the deployment of cosmic radiation over 360°long, in interplanetary space. The wide spread of this event may reflect a similar spread of coronal magnetic fields from the flare site. We interpret the solar proton data recorded by spacecraft at two separate points both at 1 AU, in terms of a two-component injection of particles at the Sun consisting of: (i) a soft component which arrived promptly; (ii) a harder component which arrived later. The radio spectral and positional data provide evidence of shock waves which propagated far and wide from the flare; we attribute the precursor injection of the soft ( 10 MeV) proton component to one of these shock waves.Radiophysics Publication RPP 1590, May, 1972.Now at University of California, LASL, Los Alamos, N.M., U.S.A.     

Some fundamental elements of universe mechanics

An essential part in the mechanics under study is taking into consideration the effect of motions of the Universe objects upon that of an individual one surrounded by them including those infinitely far from it. Only macro-objects of the Universe are meant here.

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Zusammenfassung Ein wesentlicher Bestandteil der Mechanik unter unserer Betrachtung ist die Berechnung des Einflusses auf die Bewegung eines individuellen Objektes von Bewegungen der Universum Objekte die es umringen einschließlich jene Objekte, die unendlich entfernt sind. Nur Makroobjekte des Weltalles sind in der Absicht dabei.

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Динамические равновесные плазменные конфигуации и физика магнитосферы

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Космическое черенковское излучение

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Метагалактические протоны сверхвысоких энергий

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Околозвездньiе облака поданньiм ультрафиолетовьiх спектров свезл

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Coronal Shocks of November 1997 Revisited: The Cme–Type II Timing Problem

We re-examine observations bearing on the origin of metric type II bursts for six impulsive solar events in November 1997. Previous analyses of these events indicated that the metric type IIs were due to flares (either blast waves or ejecta). Our point of departure was the study of Zhang et al. (2001) based on the Large Angle and Spectrometric Coronagraphs C1 instrument (occulting disk at 1.1 R₀) that identified the rapid acceleration phase of coronal mass ejections (CMEs) with the rise phase of soft X-ray light curves of associated flares. We find that the inferred onset of rapid CME acceleration in each of the six cases occurred 1–3 min before the onset of metric type II emission, in contrast to the results of previous studies for certain of these events that obtained CME launch times 25–45 min earlier than type II onset. The removal of the CME-metric type II timing discrepancy in these events and, more generally, the identification of the onset of the rapid acceleration phase of CMEs with the flare impulsive phase undercuts a significant argument against CMEs as metric type II shock drivers. In general, the six events exhibited: (1) ample evidence of dynamic behavior [soft X-ray ejecta, extreme ultra-violet imaging telescope (EIT) dimming onsets, and wave initiation (observed variously in H, EUV, and soft X-rays)] during the inferred fast acceleration phases of the CMEs, consistent with the cataclysmic disruption of the low solar atmosphere one would expect to be associated with a CME; and (2) an organic relationship between EIT dimmings (generally taken to be source regions of CMEs) and EIT waves (which are highly associated with metric type II bursts) indicative of a CME-driver scenario. Our analysis indicates that the broad (90 to halo) CMEs observed in the outer LASCO coronagraphs for these impulsive events began life as relatively small-scale structures, with angular spans of 15 in the low corona. A review of on-going work bearing on other aspects (than timing) of the question of the origin of metric type II bursts (CME association; connectivity of metric and decametric-hectometric type II shocks; spatial relationship between CMEs and metric shocks) leads to the conclusion that CMEs remain a strong candidate to be the principal/sole driver of metric type II shocks vis-à-vis flare blast waves/ejecta.     

Спектр и поляризация источника синхротронного излучения при релятивистском разлете его компонент

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A comparison of energetic storm protons to halo protons

Satellite observations of solar proton events with a halo structure or an energetic storm proton event and an SSC are studied. It is pointed out that some SSC events are associated with a decrease in the few MeV cosmic ray fluxes while most are associated with a flux increase. The properties of halo protons and energetic storm protons are compared. It is hypothesized that the two events are similar in origin. The propagation mode of storm particles is discussed. Evidence is presented for a solar, rather than interplanetary origin of storm protons.