Author name code: slottje ADS astronomy entries on 2022-09-14 author:Slottje, C. ------------------------------------------------------------------------ Title: Book reviews Authors: Nieuwenhuijzen, H.; Israel, F. P.; Slottje, C.; Waters, L. B. F. M.; Kleczek, J.; Werner, K.; Barylak, M.; Whitelock, Patricia; Kresák, Ľ.; Meynet, G.; van der Hucht, K. A.; Stickland, D. Bibcode: 1993SSRv...62..393N Altcode: No abstract at ADS Title: Book-Review - Tools of Radio Astronomy Authors: Rohlfs, K.; Slottje, C. Bibcode: 1993SSRv...62..394R Altcode: No abstract at ADS Title: Fine Structure in Solar Microwave Bursts Authors: Allaart, M. A. F.; van Nieuwkoop, J.; Slottje, C.; Sondaar, L. H. Bibcode: 1990SoPh..130..183A Altcode: We have designed and constructed a new multi-channel radio spectrograph for the study of short-lived structures in solar microwave bursts. It measured the integrated flux over the whole solar disc in two circular polarizations at 36 frequencies between 4 and 8 GHz, with a time constant of 0.5 ms. We have analyzed all 119 recorded bursts observed in 1981 and 1983. We focused our attention on events with a lifetime of less than 1 s. Fine structure occurs in about 30% of the observed bursts, and can be as rich in detail as in bursts observed at lower frequencies. We found at least four different classes of events. In one event neither bandwidth nor time resolution of the receiver appear to be sufficient to resolve the fine structure. The bulk of the drifts is found to be towards higher frequencies. Periodic flux variations were found in two cases. Title: Dm-Spikes and Their Relation to Other Flare Phenomena in the October 14, 1983 Event Authors: Karlický, M.; Messerotti, M.; Ruždjak, V.; Slottje, C.; Tlamicha, A.; Urpo, S.; Zlobec, P. Bibcode: 1987BAICz..38...42K Altcode: By using observations in H-alpha and radio frequencies between 169 MHz and 37 GHz, the October 14, 1983 two ribbon flare was analysed. A coherent picture of the event is given using the standard topology for two-ribbon flares and describing the dm-spikes as manifestations of electron acceleration in a reconnection process (with stationary shock wave). The drifting chains of these spikes are explained by the movement of this "stationary" shock wave. It is shown that the behaviour with time of the number density of the spikes is in agreement with that of the 37 GHz flux and hence that the same population of accelerated electrons that gave rise to the spikes, also produced the 37 GHz radiation. Title: Book-Review - the Propagation of Radio Waves Authors: Budden, K. G.; Slottje, C. Bibcode: 1986SSRv...44..184B Altcode: No abstract at ADS Title: Book reviews Authors: Gurtovenko, E. A.; Kostik, R. I.; Tlamicha, A.; Zerull, R.; Schadee, Aert; Mészáros, A.; Néeman, Y.; Giese, R. H.; Sinclair, A. T.; Kleczek, J.; Trendelenburg, E. A.; Hillebrandt, Wolfgang; Sehnal, L.; de Graaff, W.; Slottje, C.; Courvisier, T.; van Beek, H. F.; Baud, B.; de Jager, C.; Danby, J. M. A.; Somov, B. V.; Cassinelli, J.; Verbunt, F. Bibcode: 1986SSRv...44..177G Altcode: No abstract at ADS Title: Book reviews Authors: Kleczek, J.; van Gent, R. H.; Rutten, Robert J.; de Munck, J. C.; Slottje, C.; Severne, G.; Pecker, Jean-Claude; Postma, H.; Grishchuk, L. P.; Niewenhuijzen, H.; Schuiling, R. D.; van Beek, H. F.; Reijnen, G. C. M.; Heidmann, Jean; Lemaire, J.; Bleeker, Johan; Icke, V.; Neéman, Y.; Feast, M. W.; de Graaff, W. Bibcode: 1986SSRv...43..383K Altcode: No abstract at ADS Title: Book-Review - Radiotelescopes Authors: Christiansen, W. H.; Hogbom, J. A.; Slottje, C. Bibcode: 1986SSRv...43..384C Altcode: No abstract at ADS Title: Microwave, ultraviolet, and soft X-Ray observations of hale region 16898 Authors: Shibasaki, K.; Chiuderi-Drago, F.; Melozzi, M.; Slottje, C.; Antonucci, E. Bibcode: 1983SoPh...89..307S Altcode: Hale region 16898 was observed by the Westerbork Synthesis Radio Telescope at 6 cm and by the Ultraviolet Spectrometer and Polarimeter and the X-Ray Spectrometer on the Solar Maximum Mission satellite. Optical pictures of the same active region were taken at Sacramento Peak, Big Bear, and Meudon Observatories. The radio emission mechanisms are identified by comparing radio data with ultraviolet and soft X-ray data. The height of the radio sources and the magnetic field strength at that height are deduced. A radio source above a large sunspot shows a crescent shaped depression of circular polarization and a high brightness temperature. The emission mechanism is identified as gyroresonance at the second and the third harmonic layers and it is found that the second harmonic layer, where the magnetic field strength is 900 G, must be in the corona. An extended loop-like source connecting the leading and the following part of the active region as well as the sources associated with small spots are mainly due to thermal free-free emission by hot and dense plasma which is also observed in ultraviolet and soft X-ray radiation. The calculated radio brightness temperature, using the physical parameters deduced from the ultraviolet and soft X-ray line intensities, agrees with the observed brightness temperature. The height of the low brightness temperature sources above the small spots is 6000 ± 3000 km and that above the large spot is less than 3000 km: the source above the large spot does not show any shift relative to the sunspot due to the projection effect. Very strong radio emission was found which was associated with the merging of a group of small spots into the large sunspot. In the same day, warm (≤ 106 K) and dense matter was present above the large spot. Evidence for nonthermal emission is presented. Title: X-ray, Hα, and radio observations of the two-ribbon flare of 16 May, 1981 Authors: Fárník, F.; Kaastra, J.; Kálmán, B.; Karlický, M.; Slottje, C.; Valniček, B. Bibcode: 1983SoPh...89..355F Altcode: The paper is a contribution to the study of two-ribbon flares. A variety of observational material, i.e. Hα pictures, radio spectrum in the frequency band of 150-1000 MHz, radio map at 6 cm, fluxes at other frequencies, magnetograms and X-ray flux in a broad energy interval, enabled us to study the development of the 16 May, 1981 flare. The onset of the flare could be described by the model of Van Tend and Kuperus. A diminishing of the magnetic shear during the activation of the filament was observed. From radio and X-ray data it was found that pulsed acceleration took place in the region under the rising filament, the electrons propagating in a limited region both upwards to greater heights and downwards into the footpoints. Internal oscillations of the filament were observed. A manifestation of the primary process of interplanetary shock-wave generation was found. The 6 cm radio sources could be localized in the footpoints of magnetic loops. Title: VLBI of solar flares Authors: Tapping, K. F.; Kuijpers, J.; Kaastra, J. S.; van Nieuwkoop, J.; Graham, D.; Slottje, C. Bibcode: 1983A&A...122..177T Altcode: From April 28 to May 3, 1981, a VLBI experiment was carried out to observe small spatial scales in the initial energy release in solar flares. The 25 m radio telescope at Onsala (Sweden) and Dwingeloo (Netherlands) were used; the observing wavelength was 18 cm. Simultaneous observations were made using the Westerbork Synthesis Radio Telescope at a wavelength of 6 cm. The VLBI baseline was 619 km. During the observing period, three weak outbursts were observed, none yielding any strong correlated signals. However, the statistical behaviour of the correlator output over the range of delay channels shows significant indications of a correlated signal having a signal to noise ratio of order unity, during the impulsive spikes preceding the main phase of the event. Title: Multiple Wavelength Observations of a Solar Active Region Authors: Chiuderi-Drago, F.; Bandiera, R.; Willson, R. F.; Slottje, C.; Falciani, R.; Antonucci, E.; Lang, K. R.; Shibasaki, K. Bibcode: 1982SoPh...80...71C Altcode: The Solar Maximum Mission Satellite, the Sacramento Peak Vacuum Tower Telescope, the Very Large Array and the Westerbork Synthesis Radio Telescope have been used to observe active region AR 2490 on two consecutive days at soft X-ray, ultraviolet, optical and radio wavelengths (2, 6, and 20 cm), with comparable angular resolution (2″ to 15″) and field of view (4' × 4'). The radio emissions at λ = 6 cm and 20 cm show a double structure in which one component is associated with bright Hα plage, C IV and soft X-ray emission, and the other component is associated only with sunspots. No radiation at λ = 2 cm is detected in this latter component. Coronal temperature and emission measure derived from X-ray lines indicate that the dominant radiation mechanism of the plage-associated component is due to thermal bremsstrahlung while the gyroresonance absorption coefficient must be invoked to account for the high brightness temperature (Tb≈2×106K) observed in the sunspot associated component. The high magnetic field strength needed (600 G at a level where T∼2×106K) is explained assuming a thin transition zone, in order to reach a high electron temperature close to the sunspot, where the magnetic fields are stronger. A higher temperature gradient above sunspots is also consistent with the absence of detectable C IV emission. Title: The Relation Between the Surges and Solar Radio Emission Authors: Garczynska, I. N.; Rompolt, B.; Benz, A. O.; Slottje, C.; Tlamicha, A.; Zanelli, C. Bibcode: 1982SoPh...77..277G Altcode: The 120 limb surges which have been observed by means of Wrocław Observatory coronagraph from September 1966 to November 1977 are investigated. The evolution of surges was compared with the radio data during the surges. A correlation between radio bursts and the surges was found, particularly with chains of type I radio bursts, which is the first reliable correlation found of these bursts with non-radio events. The type I correlation only applied for surges without accompanying flare, of which 43% are correlated with this type of radio emission. In 23 of 30 associated events the start of a surge coincided within 5 minutes with the start or an enhancement of the type I storm. If flares were present, the association was not significant. Title: Atlas of fine structures of dynamic spectra Authors: Slottje, Cornelis Bibcode: 1982PhDT.......179S Altcode: No abstract at ADS Title: Runaway acceleration in a radio flare Authors: Kuijpers, J.; van der Post, P.; Slottje, C. Bibcode: 1981A&A...103..331K Altcode: Radio observations of a solar flare are explained by induced electric fields in several small regions within a flaring flux tube. In each acceleration region runaway electrons are produced which lead to a pulsed production of high-frequency plasma waves. The model is used for an accurate determination of the physical conditions in the flare. During the runaway process an essential fraction of the runaway energy is put into plasma waves. The required electric field strength is of order E/Ec approximately equal to 0.1 (Ec is twice the Dreicer field) and the ratio of electron cyclotron to plasma frequency is of order unity or larger. Title: Simultaneous Calibration of Solar Radio Instruments from Decimetre to Decametre Wavelengths Authors: Elgaroy, O.; Slottje, C.; Tlamicha, A.; Urbarz, H.; Zanelli, C.; Zlobec, P.; Bougeret, J. L.; Kerdraon, A.; de La Noe, J. Bibcode: 1981A&AS...44..165E Altcode: Simultaneous calibration of about 15 solar radio instruments in Europe on a day when the spectrum of the solar radio emission was stable snows satisfactory concordance despite the diversity of the instruments and the use of various methods of calibration.

The results obtained will serve as a common basis for the study of noise storm continua - and also of other radio spectra - in the dm-dam wavelength range. Title: Fast fine structure in solar microwave flares Authors: Slottje, C. Bibcode: 1980IAUS...86..195S Altcode: A preliminary account is presented of some characteristics of Fast Fine Structure, that is fine structure with time scales in the millisecond range, and of the flare events in which the appear. Fast Fine Structure is found to be a fairly common phenomenon that could, but not necessarily does, appear in flare events of any importance occurring at any longitude. It may occur with any type of microwave burst (except most likely 'Rise' and 'Fall'). It appears more often in the more important events and it may last for only a few seconds up to many minutes. Fast Fine Structure may have any degree of circular polarization, apparently independent of its longitude position. Title: Millisecond microwave spikes in a solar flare Authors: Slottje, C. Bibcode: 1978Natur.275..520S Altcode: THE shortest-lived structures in microwave solar flares known until now last ~1 s. Recently (11 April 1978) we observed a microwave outburst at 2.65 GHz (starting at 13.41 UT) showing a strong and extremely fast fluctuating burst component. Many spikes appeared to have half-power durations smaller than the 20-ms resolution of the instrument used. These are about two orders of magnitude shorter-lived than events reported from previous microwave observations. They are only rivalled by fine structure in some decimetric type IV bursts between 0.4 and 1.4GHz (ref. 1). Title: Polarization and location of metric radiobursts in relationship with the emergence of a new magnetic field. Authors: Heyvaerts, J.; Kerdraon, A.; Mangeney, A.; Pick, M.; Slottje, C. Bibcode: 1978A&A....66...81H Altcode: Spike bursts have been observed in association with some solar type III burst groups. In this event, the spikes appear according to bandwidth and duration to be mini type I bursts. Their circular polarization cannot be explained by emission of the ordinary mode in the magnetic field of the dominant photospheric polarity. This observation is interpreted by the expansion at 0.3 solar radii of magnetic loops related to the emergence of a satellite polarity. A coronal-field model is proposed for the whole active center. Application of the theory of Mangeney and Veltri (1976) for type I bursts leads to a consistent picture of the generation of these spikes. Title: The quiet solar background between 160 and 320 MHz. Calibrated measurements with the 60-channel radio spectrograph at Dwingeloo Authors: Slottje, C. Bibcode: 1978cesra...7...35S Altcode: No abstract at ADS Title: Some spectra of noise storm continua between 160 and 320 MHz during August 1976 Authors: Slottje, C. Bibcode: 1978cesra...7...33S Altcode: No abstract at ADS Title: Some measurements of noise storm brightness temperatures at 243 MHz Authors: Slottje, C. Bibcode: 1978cesra...7...38S Altcode: No abstract at ADS Title: The "Continuum group" Authors: Slottje, C. Bibcode: 1978cesra...7...49S Altcode: No abstract at ADS Title: Chains of type I stormbursts. Authors: de Groot, T.; Loonen, J.; Slottje, C. Bibcode: 1976SoPh...48..321D Altcode: From radio spectra between 160 and 320 MHz of chains of type I bursts it appears that their duration distributions allow an exponential fit, and that those of samples containing long and short chains respectively, taken from the same storm, have virtually the same characteristic time (logarithmic slope). On the average this figure decreases - as a function of the frequency - at about 1 s per 10 MHz. The high frequency cut-off of chain activity (noise storms) is mainly a consequence of the frequency dependence of the probability for the first burst of a chain to appear. Given the density of type I bursts in a chain, it is concluded that the probability of a type I burst to be followed by another one is at least 90% below 250 MHz and 70-80% at 300 MHz, which makes it essential for type I theories to include a mechanism to this effect. The drift rate distribution for chains is symmetrical with a peak at-10 MHz/s. The statistics is indicative of a correlation between drift rate and duration. No evidence has been found for the occurrence of chain pairs or frequency splitting in chains, nor for an association between chains and type III bursts. Title: Fiber burst concurrent with a weak noise storm. Authors: Kuijpers, J.; Slottje, C. Bibcode: 1976SoPh...46..247K Altcode: A new kind of radio burst is described and identified as quasi-fiber burst according to some striking similarities with fiber bursts. Its interpretation is discussed in terms of Kuijpers' whistler model and an explanation for a broken variety of. the observed burst is given. The derived magnetic field strength in the source is 4 G at a plasma level of 300 MHz. Title: Polarization Fine Structure in Solar Radiobursts of Type III on Short Meter Wavelengths Authors: Slottje, C. Bibcode: 1974A&A....32..107S Altcode: Summary. Accurately calibrated measurements with the 60-Channels Solar Radiospectrograph, now operated at Dwingeloo between 315 and 200 MHz, led to the discovery of finestructure in the timeprofile of the degree of polarization of some Type III bursts: after a short peak of very high values the polarization drops to about 10% while the intensity increases to its maximum. This behaviour is in agreement with a model given by Fomichev and Chertok. A more sophisticated model enables to deduce from the observed polarization profile and frequency driftrate, consistent values for the magnetic field strength in the source, the density gradient of the ambient plasma and the exciter speed. As the model predicts a different polarization profile for fundamental and harmonic radiation respectively the bursts of the present case are identified as fundamental radiation. Key words: Sun - radiobursts - type III - polarization Title: High Resolution Studies of Type III Solar Radio Bursts (presented by H. Rosenberg) Authors: Chiuderi, C.; Giachetti, R.; Mercier, C.; Rosenberg, H.; Slottje, C. Bibcode: 1974IAUS...57..225C Altcode: No abstract at ADS Title: Fine Structure in Type IV Solar Radio Bursts (presented by H. Rosenberg) Authors: Caroubalos, C.; Pick, M.; Chiuderi, C.; Giachetti, R.; Rosenberg, H.; Slottje, C. Bibcode: 1974IAUS...57..291C Altcode: No abstract at ADS Title: Polarization Fine Structure of Type III Solar Radio Bursts on Short Meter Wavelengths and its Relation to the Nature of the Radiation and Source Parameters Authors: Slottje, C. Bibcode: 1974cesra...4...71S Altcode: No abstract at ADS Title: A High Resolution Study in Times, Position, Intensity, and Frequency of the Radio Event of January 14, 1971 Authors: Caroubalos, C.; Pick, M.; Rosenberg, H.; Slottje, C. Bibcode: 1973SoPh...30..473C Altcode: A high resolution study in time, frequency, position, and intensity was made at 169 MHz and neighbouring frequencies of the solar radio event of 1971, January 14, 11h 20m-30m UT. The event consisted of two closely resembling groups of type III bursts and type II like details. Title: A High Resolution Study in Time, Position, Intensity, and Frequency of a Radio Event on January 14, 1971 Authors: Caroubalos, C.; Pick, M.; Rosenberg, H.; Slottje, C. Bibcode: 1973NASSP.342..610C Altcode: 1973heps.conf..610C No abstract at ADS Title: Addendum: "Peculiar absorption and emission microstructures in the type IV solar radio outburst of March 2, 1970" [Sol. Phys., Vol. 25, p. 210 - 231 (1972)]. Authors: Slottje, C. Bibcode: 1972SoPh...26..259S Altcode: No abstract at ADS Title: Peculiar absorption and emission microstructures in the type IV solar radio outburst of March 2, 1970 Authors: Slottje, C. Bibcode: 1972SoPh...25..210S Altcode: The high resolution dynamic spectrogram between 320 and 160 MHz of the Type IV event which started at 13∶35 UT on the 2nd of March 1970 shows a remarkable richness of absorption-emission microstructures. These are morphologically analyzed into structure elements and patterns. The elements are normal and reversed intermediate drift bursts, which we call fiber bursts, medium band shortlived absorptions, broadband shortlived absorptions, broadband wedge shaped absorptions and a, sofar unknown, type which we call tadpole. The patterns are the pulsating structure, sequences of broadband shortlived absorptions, and patterns of almost parallel lines which we call zebra patterns. Title: First results of digitally recording radiospectra with the 60-channel radio spectrograph Authors: Slottje, C. Bibcode: 1972cesra...3..159S Altcode: No abstract at ADS Title: A high resolution study in time, position, intensity and frequency of a radio event on January 14, 1971 Authors: Caroubalos, C.; Pick, M.; Rosenberg, H.; Slottje, C. Bibcode: 1972cesra...3..162C Altcode: No abstract at ADS Title: A new site for the solar radio observations in the Netherlands Authors: Slottje, C. Bibcode: 1972cesra...3..216S Altcode: No abstract at ADS Title: Fine structure in spectra of solar radio bursts Authors: Slottje, C. Bibcode: 1972ppsr.conf..245S Altcode: No abstract at ADS Title: Peculiar absorption and emission microstructures in a Type IV solar radio outburst Authors: Slottje, C. Bibcode: 1971cesra...1...40S Altcode: No abstract at ADS Title: Zebra patterns in solar type IV radio bursts Authors: Slottje, C. Bibcode: 1971cesra...2...88S Altcode: No abstract at ADS