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  • 1
    Electronic Resource
    Electronic Resource
    Energetic particle investigation using the ERNE instrument (1996)
    Springer
    Annales geophysicae 14 (1996), S. 497-502 
    Details
    ISSN: 0992-7689
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract During solar flares and coronal mass ejections, nuclei and electrons accelerated to high energies are injected into interplanetary space. These accelerated particles can be detected at the SOHO satellite by the ERNE instrument. From the data produced by the instrument, it is possible to identify the particles and to calculate their energy and direction of propagation. Depending on variable coronal/interplanetary conditions, different kinds of effects on the energetic particle transport can be predicted. The problems of interest include, for example, the effects of particle properties (mass, charge, energy, and propagation direction) on the particle transport, the particle energy changes in the transport process, and the effects the energetic particles have on the solar-wind plasma. The evolution of the distribution function of the energetic particles can be measured with ERNE to a better accuracy than ever before. This gives us the opportunity to contribute significantly to the modeling of interplanetary transport and acceleration. Once the acceleration/transport bias has been removed, the acceleration-site abundance of elements and their isotopes can be studied in detail and compared with spectroscopic observations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-996-0497-5
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  • 2
    Electronic Resource
    Electronic Resource
    Performance of ERNE in particle flux anisotropy measurement (1996)
    Springer
    Annales geophysicae 14 (1996), S. 503-509 
    Details
    ISSN: 0992-7689
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The HED particle detector of the ERNE experiment to be flown on the SOHO spacecraft is unique compared to the earlier space-born detectors in its high directional resolution (better than 2°, depending on the track inclination). Despite the fixed view cone due to the three-axis stabilization of the spacecraft, the good angular and temporal resolution of the detector provides a new kind of opportunity for monitoring in detail the development of the anisotropies pertaining, for example, to the onset of SEP events, or passage of shock fronts related to gradual events. In order to optimize the measurement parameters, we have made a preflight simulation study of the HED anisotropy measurement capabilities. The purpose was to prove the feasibility of the selected measurement method and find the physical limits for the HED anisotropy detection. The results show HED to be capable of detecting both strong anisotropies related to impulsive events, and smoother anisotropies associated with gradual events.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-996-0503-y
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  • 3
    Electronic Resource
    Electronic Resource
    Long-duration high-energy proton events observed by GOES in October 1989 (1998)
    Springer
    Annales geophysicae 16 (1998), S. 921-930 
    Details
    ISSN: 0992-7689
    Keywords: Interplanetary physics ; Energetic particles ; Solar physics, astrophysics and astronomy ; Flares and mass ejections
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract We consider the prolonged injection of the high-energy (〉 10 MeV) protons during the three successive events observed by GOES in October 1989. We apply a solar-rotation-stereoscopy approach to study the injection of the accelerated particles from the CME-driven interplanetary shock waves in order to find out how the effectiveness of the particle acceleration and/or escape depends on the angular distance from the shock axis. We use an empirical model for the proton injection at the shock and a standard model of the interplanetary transport. The model can reproduce rather well the observed intensity-time profiles of the October 1989 events. The deduced proton injection rate is highest at the nose of the shock; the injection spectrum is always harder near the Sun. The results seem to be consistent with the scheme that the CME-driven interplanetary shock waves accelerate a seed particle population of coronal origin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-998-0921-0
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  • 4
    Electronic Resource
    Electronic Resource
    Biocompatibility of silicon carbide in colony formation test in vitro (1998)
    Springer
    Archives of orthopaedic and trauma surgery 118 (1998), S. 89-91 
    Details
    ISSN: 1434-3916
    Keywords: Key words Biocompatibility ; Total hip replacement ; Prosthesis coating ; Ceramics ; Silicon carbide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We studied the possible use of silicon carbide (SiC) as a ceramic coating material of titanium-based total hip replacement (THR) implants. The idea is to prevent wear debris formation from the soft titanium surface. SiC is a hard and tightly bonding ceramic surface material, and because of these physical properties it is not easily degradable, as is the case with hydroxyapatite. Our previous in vivo and in vitro studies have indicated that SiC and hydroxyapatite are equally biocompatible regarding particle size for phagocytosis. The present cytotoxicity test using JCRB0603 cells showed that 5 μm SiC particles inhibited colony outgrowth by one-third (67% + 10% vs control), while SiC-coated pins did not cause any inhibition and acted similarly to uncoated titanium pins. The results support the hypothesis that SiC is a promising ceramic THR implant coating material.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004020050319
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  • 5
    Electronic Resource
    Electronic Resource
    Energies of carbon plasma beams in the deposition of diamond-like coatings with the pulsed-arc-discharge method (1995)
    Springer
    Applied physics 61 (1995), S. 353-355 
    Details
    ISSN: 1432-0630
    Keywords: 81.15 ; 81.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The carbon plasma ion energies produced by the pulsed filtered arc-discharge method have been measured as a function of the anode-cathode voltage. The energies were determined by using the electro-optical time-of-flight method. The highest anode-cathode voltage was 5 kV and yielded the energy of 140 eV for the plasma ions. In addition, it was demonstrated that a rather slight change of the parameters in the arc-discharge method has a strong effect on the plasma ion energies and the properties of the diamond-like coatings prepared.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01540107
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  • 6
    Electronic Resource
    Electronic Resource
    Energies of carbon plasma beams in the deposition of diamond-like coatings with the pulsed-arc-discharge method (1995)
    Springer
    Applied physics 61 (1995), S. 353-355 
    Details
    ISSN: 1432-0630
    Keywords: PACS: 81.15; 81.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract.  The carbon plasma ion energies produced by the pulsed filtered arc-discharge method have been measured as a function of the anode–cathode voltage. The energies were determined by using the electro-optical time-of-flight method. The highest anode–cathode voltage was 4 kV and yielded the energy of 140 eV for the plasma ions. In addition, it was demonstrated that a rather slight change of the parameters in the arc-discharge method has a strong effect on the plasma ion energies and the properties of the diamond-like coatings prepared.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01540107
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  • 7
    Electronic Resource
    Electronic Resource
    Recurrence of Energetic Particle Flux Anisotropy as Observed by Erne on 9 July 1996 (1997)
    Springer
    Solar physics 175 (1997), S. 771-784 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A solar energetic particle event was observed on 9 July 1996, by the ERNE sensors LED and HED on board the SOHO spacecraft. The arrival of the first protons in the energy range 〉20 MeV took place at 09:55 UT, 43 min after the maximum in the X-ray and Hα radiation of a flare located at S10 W30. The rise phase of the particle intensities at all energies was exceptionally rapid. At 12:50 UT, the intensities dropped in all energy channels. Simultaneously, the magnetic field instrument MFI on board WIND, not far from SOHO, detected a sharp and large change in the magnetic field direction. The analysis of the directional measurements of ERNE in the energy range 14–17 MeV shows the presence of a strong flux anisotropy during the whole period 10:10–12:50 UT. From 12:50 UT until about 16:00 UT, the directional analysis of the proton fluxes gives only a weak anisotropy at the limit of the sensor resolution. Later on, the flux anisotropy was found to recur, indicating a continuous injection of particles into the flux tubes connected to the SOHO spacecraft. These experimental results lead to strict limits on particle injection and transport models. The first period of the anisotropy and its recurrent phase cover 24 hours. This suggests an extended injection of particles. The strength and stability of the anisotropy indicate that, during these periods, SOHO was in an interplanetary sector where the particle transport was almost scatter-free. On the other hand, during the intermediate 3-hr period, we observed particles which traveled in a sector of diffusive transport or which were retarded by magnetic field disturbances not far from the observation site.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004944222260
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  • 8
    Electronic Resource
    Electronic Resource
    The 1990 May 24 solar cosmic-ray event (1996)
    Springer
    Solar physics 166 (1996), S. 135-158 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract 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 γ ≈ 1.6) at lower energies (∼ 30 MeV) with a rapid steepening above 300 MeV. Large values of the mean free path (λ ≈ 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00179359
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  • 9
    Electronic Resource
    Electronic Resource
    Anomalous Cosmic-Ray Helium, Nitrogen and Oxygen in 1996 – Measurements of the ERNE Instrument on-board SOHO (1997)
    Springer
    Solar physics 170 (1997), S. 193-204 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The energy spectra of the anomalous components of helium, nitrogen and oxygen have been measured by the ERNE experiment on board the SOHO spacecraft. During February 28–April 30, 1996, the maximum intensity of anomalous helium was found to be 3.8 × 10-5 cm-2 sr-1 s-1 (MeV nucl-1)-1 in the energy range 10–15 MeV nucl-1. During the period January 26–April 30, 1996, the maximum oxygen intensity was 1.2 × 10-5 cm-2 sr-1 s-1 (MeV nucl-1)-1 at 4–7 MeV nucl-1, and the maximum nitrogen intensity 1.7 × 10-6 cm-2 sr-1 s-1 (MeV nucl-1)-1 at 4–9 MeV nucl-1. These peak intensities are at the same level as two solar cycles ago in 1977, but significantly higher than in 1986. This gives observational evidence for a 22-year solar modulation cycle. A noteworthy point is that the spectra of anomalous nitrogen and oxygen appear to be somewhat broader than in 1977.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004911017315
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  • 10
    Electronic Resource
    Electronic Resource
    First Energetic Particle Events Observed by the ERNE Instrument (1997)
    Springer
    Solar physics 170 (1997), S. 179-191 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The energetic particle instrument ERNE on-board SOHO started its observations on December 15, 1995. The low-energy sensor of ERNE, LED, is capable of measuring particles in the energy range from 1 to 10 MeV nucl-1. From the beginning of the year 1996 until May 22, 1996, LED-observations included four energetic particle events above threshold intensities. An energetic particle event caused by a corotating interaction region that accelerated protons upto ∽ 10 MeV, was observed during January 20–25. Another similar particle event occured on May 6–12. The events were separated by four solar rotation periods. They had similar time profiles, but the one in May had a harder spectrum and a lower intensity level. The 4He-to-proton ratios were in accordance with the solar wind value. Energetic particles observed during April 22–23 and May 14–17 were accelerated at the Sun. The first one was apparently an outcome from an active region observed on the west limb by telescopes on-board SOHO. Protons were detected at energies from 1 to ∽10 MeV. For this event, the4He-to-proton ratio in the range 1.5–5 MeV nucl-1 was ∽ 3%. No 3He ions were detected. The period of May 14–15 was, in contrast, extremely 3He-rich: it had a3He-to-proton ratio of 1.5 ± 0.6 and a 3He-to- 4He ratio as high as ∽ 8. The period of May 14–17 comprised at least three individual, one-day-long events. The first two events were 3He-rich, while the last one seemed to have a normal composition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004963118224
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