Author name code: vannieuwkoop
ADS astronomy entries on 2022-09-14
author:van Nieuwkoop, Jaap year:1960-2000
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Title: Book reviews
Authors: Humphreys, R. M.; Kemp, S.; Savonije, G.; van der Hucht,
   K. A.; van der Kruit, P. C.; Miley, G.; Bumba, V.; van Nieuwkoop,
   J.; van Hoolst, T.; Cox, A.; Rutten, R. J.; Kleczek, J.; de Jager,
   Cornelis; Jerzykiewicz, M.; Zwaan, C.; Poedts, S.; Sakai, Jun-Ichi;
   Pecker, J. -C.; Heikkila, W.; de Jong, T.; Wilson, P. R.; Müller,
   E. A.; Hoyng, P.; Icke, V.; Shore, S. N.; Achterberg, A.; Lucchin, F.;
   Butcher, H.; Ne'Eman, Y.; Heidmann, J.; Belton, M. J. S.; de Graauw,
   Th.; Waters, L. B. F. M.; Pacini, F.; Hultqvist, B.; Akasofu, S. -I.;
   Vial, J. -C.; Schatzman, E.; van der Laan, H.; Cole, K. D.; Vanbeveren,
   D.; Southwood, D.; van der Klis, M.; Katgert, Peter
Bibcode: 1996SSRv...76..339H
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: Positional Drift Within Groups of Type-I Solar Radio Bursts
Authors: van Nieuwkoop, J.
Bibcode: 1986SoPh..103..129V
Altcode:
  In the dynamic spectrograms of the 60-channel solar radiospectrograph at
  Dwingeloo coherent groups of Type I bursts have been selected. At 243
  MHz the positions of the bursts were measured. Within many groups the
  bursts showed a systematic angular displacement with time. Movements
  with apparent velocities up to 15000 km s<SUP>−1</SUP> have been
  observed. The burst positions have been obtained with a two-element
  interferometer. A special data reduction method used the amplitude
  variation of the Type I bursts as a parameter for selection against
  the background radiation.

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: Digitally recorded type I bursts and some theoretical aspects
    of continuum and burst generation
Authors: Kattenberg, A.; van Hees, R. M.; van Nieuwkoop, J.
Bibcode: 1980IAUS...86..259K
Altcode:
  An analysis of digitally recorded type-I bursts is presented. The
  reduction procedure is described and some typical examples and results
  are presented. A model for type-I emission, compatible with low magnetic
  field strengths, is proposed. Incoherent Langmuir waves, spontaneously
  emitted by trapped fast electrons, are converted to transverse radiation
  by coalescence with low-frequency whistlers. Recurrent upper hybrid
  instability in strong MHD pulses explains the bursts in this model.

Title: Radioastronomische waarneemtechnieken: 1950 - 1980.
Authors: van Nieuwkoop, J.
Bibcode: 1980Zenit...7..416V
Altcode:
  No abstract at ADS

Title: A model of type I emission compatible with low magnetic
    field strengths
Authors: van Hees, R. M.; van Nieuwkoop, J.
Bibcode: 1978cesra...7...44V
Altcode:
  No abstract at ADS

Title: Book reviews
Authors: Nieuwenhuijzen, H.; van den Heuvel, E. P. J.; Heintze,
   J. R. W.; Hultqvist, Bengt; van Nieuwkoop, J.; 't Hooft, G.; Raadu,
   M. A.; Zealey, W. J.; Verhulst, Ferdinand; Boström, Rolf; Schindler,
   K.
Bibcode: 1976SSRv...19..273N
Altcode:
  No abstract at ADS

Title: De nijmeegse radio-interferometer.
Authors: Atanasijevic, I.; Bluyssen, H.; Dongen, L. V.; ten Horn,
   L.; Maas, L.; van Nieuwkoop, J.
Bibcode: 1975dnr..book.....A
Altcode:
  No abstract at ADS

Title: Some preliminary results of multi-channel radiospectrography
Authors: De Groot, T.; Van Nieuwkoop, J.
Bibcode: 1968SoPh....4..332D
Altcode:
  No abstract at ADS

Title: A Radio Spectrograph with High Sensitivity and High Time
    Resolution
Authors: van Nieuwkoop, J.
Bibcode: 1964Natur.201..380V
Altcode:
  WORK has recently been done on the fine structure in time of solar
  radio emission. This fine structure is characterized by short-lived
  variations of the intensity; they may have either small or large
  intensities<SUP>1</SUP>.