Dynamics of blinkers

D Bewsher, Clare Elizabeth Parnell, CD Pike, RA Harrison

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

The relative Doppler and non-thermal velocities of quiet-Sun and active-region blinkers identified in O V with CDS are calculated. Relative velocities for the corresponding chromospheric plasma below are also determined using the He I line. O V blinkers and the chromosphere directly below, have a preference to be more red-shifted than the normal transition region and chromospheric plasma. The ranges of these enhanced velocities, however, are no larger than the typical spread of Doppler velocities in these regions. The anticipated ranges of Doppler velocities of blinkers are 10 - 15 km s(-1) in the quiet Sun (10 - 20 km s(-1) in active regions) for He I and 25 - 30 km s(-1) in the quiet Sun (20 - 40 km s(-1) in active regions) for O V. Blinkers and the chromosphere below also have preferentially larger non-thermal velocities than the typical background chromosphere and transition region. Again the increase in magnitude of these non-thermal velocities is no greater than the typical ranges of non-thermal velocities. The ranges of non-thermal velocities of blinkers in both the quiet Sun and active regions are estimated to be 15 - 25 km s(-1) in He I and 30 - 45 km s(-1) in O V. There are more blinkers with larger Doppler and non-thermal velocities than would be expected in the whole of the chromosphere and transition region. The recently suggested mechanisms for blinkers are revisited and discussed further in light of the new results.

Original languageEnglish
Pages (from-to)217-237
Number of pages21
JournalSolar Physics
Volume215
Publication statusPublished - Aug 2003

Keywords

  • SOLAR TRANSITION REGION
  • DOPPLER WAVELENGTH SHIFTS
  • QUIET-SUN
  • ACTIVE REGIONS
  • LINE-PROFILES
  • EMISSION-LINE
  • SUMER
  • VELOCITIES
  • SPECTRA
  • SOHO

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