排序方式： 共有8条查询结果，搜索用时 13 毫秒
1
1.
T. L. Lim J. J. Quenby M. K. Reuss E. Keppler H. Kunow B. Heber R. J. Forsyth 《Annales Geophysicae》1996,14(4):400-410
During November 1992, a series of forward and reverse shocks passed the ULYSSES spacecraft. Spectral and anisotropy measurements are reported for protons and alpha particles between 0.28 and 6 MeV observed by the Energetic Particle Composition Experiment, data recorded by the Magnetometer Experiment and the high-energy (2.7-300 MeV) proton data from the Kiel Electron Telescope. An analysis of energetic particle, plasma and magnetometer data from ULYSSES has allowed a unique study of the corresponding arrival of fare particles, particles within a corotating interaction region and particles transported with a coronal mass ejection. We present an analysis of these data in terms of possible diffusive shock acceleration but conclude that this is likely to be incompatible with the short transit time of the particles. Shock drift acceleration of particles with energies 0.3 MeV/nucleon or solar acceleration followed by particle trapping behind the shock front are alternative possibilities. 相似文献
2.
Gómez-Herrero Raúl RodrÍguez-FrÍas M. Dolores del Peral Luis Sequeiros Juan Müller-Mellin Reinhold Kunow Horst Sierks Holger 《Solar physics》2000,194(2):405-413
An analysis of the hydrogen and helium isotopic composition from EPHIN data, during the quiet-time period from January 1 to June 1, 1996, is presented. An isotopic discrimination and background rejection have been applied and relationships between the abundances of 2H/1H, 3He/4He, and 4He/1H have been calculated. The energy spectra in the 4–50 MeV nucl–1 range have been obtained and the contribution of the different spectral components have been analysed in this energy range. We conclude that the main contribution to the 4He spectrum is of anomalous origin, while the proton and 3He spectra have contributions mainly from particles of solar origin at low energies and from the galactic cosmic radiation modulated by the heliosphere at high energies. The deuterium spectrum is mainly of galactic origin. 相似文献
3.
4.
G. Mann H.-T. Classen U. Motschmann H. Kunow W. Dröge 《Astrophysics and Space Science》1998,264(1-4):489-496
Combined SOHO (Solar and Helisopheric Observatory) and ground based radio observations show evidently signatures of electrons
accelerated by a shock wave during the event on July 9, 1996. A solar type II radio burst has been received as a signature
of a coronal shock wave at 300 MHz on 9:10:54 UT. It was accompanied with electron beams appearing as type III radio bursts
below 80 MHz. Simultaneously, the COSTEP (Comprehensive Suprathermal and Energetic Particle Analyzer) instrument aboard SOHO
has measured enhanced electron fluxes in the range 30 keV – 3 MeV. This indicates that a coronal shock wave was able to produce
high energetic electrons. A mechanism of electron acceleration up to relativistic velocities is presented and compared with
the observations. The electron acceleration takes place at substructures of quasi-parallel collisionless shocks.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
J. Clem W. Droege P. A. Evenson H. Fischer G. Green D. Huber H. Kunow D. Seckel 《Astroparticle Physics》2002,16(4):1145-395
We present results from the initial flight of our Balloon Air CHerenkov (BACH) payload. BACH detects air Cherenkov radiation from cosmic ray nuclei as coincident flashes in two optical modules. The flight (dubbed PDQ–BACH) took place on April 22, 1998 from Ft. Sumner, New Mexico. During an exposure of 2.75 h, with a typical threshold energy for iron nuclei of 2.2×1013 eV, we observed several events cleanly identifiable as iron group nuclei. Analysis of the data yields a new flux measurement that is fully consistent with that reported by other investigations. 相似文献
6.
7.
M. -B. Kallenrode G. Wibberenz H. Kunow R. Müller-Mellin V. Stolpovskii N. Kontor 《Solar physics》1993,147(2):377-410
We present a sample of solar energetic particle events observed between November 18 and December 31, 1982 by the HELIOS 1, the VENERA 13, and IMP 8 spacecraft. During the entire time period all three spacecraft were magnetically connected to the western hemisphere of the Sun with varying radial and angular distances from the flares. Eleven proton events, all of them associated with interplanetary shocks, were observed by the three spacecraft. These events are visible in the low-energy (about 4 MeV) as well as the high-energy (30 MeV) protons. In the largest events protons were observed up to energies of about 100 MeV. The shocks were rather fast and in some cases extended to more than 90% east of the flare site. Assuming a symmetrical configuration, this would correspond to a total angular extent of some interplanetary shocks of about 180%. In addition, due to the use of three spacecraft at different locations we find some indication for the shape of the shock front: the shocks are fastest close to the flare normal and are slower at the eastern flank. For particle acceleration we find that close to the flare normal the shock is most effective in accelerating energetic particles. This efficiency decreases for observers connected to the eastern flank of the shock. In this case, the efficiency of shock acceleration for high-energy protons decreases faster than for low-energy protons. Observation of the time-intensity profiles combined with variations of the anisotropy and of the steepness of the proton spectrum allows one in general to define two components of an event which we term solar and interplanetary. We attempt to describe the results in terms of a radially variable efficiency of shock acceleration. Under the assumption that the shock is responsible not only for the interplanetary, but also for the solar component, we find evidence for a very efficient particle acceleration while the shock is still close to the Sun, e.g., in the corona. In addition, we discuss this series of strong flares and interplanetary shocks as a possible source for the formation of a superevent. 相似文献
8.
G. Wibberenz K. Kecskeméty H. Kunow A. Somogyi B. Iwers Yu. I. Logachev V. G. Stolpovskii 《Solar physics》1989,124(2):353-392
We present a new method to separate interplanetary and coronal propagation, starting from intensity variations observed by spaceprobes at different heliolongitudes. In general, a decrease in absolute intensities is observed simultaneously with an increase in temporal delays. The coupling of these two effects can be described by Reid's model of coronal diffusion and can in principle be used to determine the two coronal time constants, diffusion time t
c
and escape time A. In addition, a least-squares fit method is used to determine the parameters of interplanetary transport, assuming a radial dependence as (r) = 0(r/1 AU)b. The method is applied to the two solar events of 27 December, 1977 and 1 January, 1978 which were observed by the spaceprobes Helios 1, Helios 2, and Prognoz 6. Energetic particle data are analysed for 13–27 MeV protons and -0.5 MeV electrons. For the regions in space encountered during these events the mean free path of electrons is smaller than that of protons. Straight interpolation between the two rigidities leads to a rather flat rigidity dependence (P) P
n
with n = 0.17–0.25. This contradicts the prediction of a constant mean free path or of the transition to scatter-free propagation below about 100 MV rigidity. In three of the four cases the mean free path of 13–27 MeV protons is of the order 0.17 AU, the mean free path of electrons of the order 0.06 AU. For protons we find b - 0.7 for the exponent of the radial variation.The concept of two different coronal propagation regimes is confirmed. It is remarkable that in both regimes electrons are transported more efficiently than protons. This holds for the temporal delay as well as for the amplitude decrease. This is in contrast with the long existing concept of rigidity independent transport and puts severe limits to any model of coronal transport. For the December event all three spaceprobes are in the fast propagation regime up to an angular distance of 62°. For protons we find a finite delay even in the fast propagation region, corresponding to a coronal delay rate of about 0.8 hr rad-1 up to 60° angular distance. In contrast, relativistic electrons may reach this distance within a few minutes.The fast transport of electrons and the different behaviour of electrons and protons is in contradiction to the expanding bottle concept. An explanation of coronal transport by shock acceleration directly on open field lines could in principle work in case of protons in the fast propagation region, but would fail in case of the electrons. The fast and efficient transport of electrons is most likely due to a region of field lines extending over a wide range of longitudes directly from the active region into interplanetary space. The much slower transport of both particle types at large azimuthal distances can neither be explained by direct access to open field lines not by the direct shock acceleration concept. A possible explanation is the loop reconnection model in a modified version, allowing for a faster lateral transport of electrons.Now at AEG, 2000 Wedel, F.R.G. 相似文献
1