Letter | Published:

Interpretation of Solar Hard X-ray Burst Polarisation Measurements

Naturevolume 247pages448449 (1974) | Download Citation

Subjects

Abstract

TINDO et al. (refs 1 to 3 and unpublished results) have reported the first observations of polarisation of solar flare emission in the hard X-ray band (around 15 keV) and have made a preliminary interpretation of these3. Their results depend, however, on the removal of systematic differences in sensitivity of the detectors used in the Intercosmos Thomson-scattering polarimeters, by calibration on an ‘unpolarised’ source. We point out here that the results as presented by Tindo et al. are in fact in error since their calibration was based on the assumption that the hard X-ray flux from the flare itself tends to zero polarisation in its final stages of decay. This assumption is invalidated by the presence, in the total flux, of a large polarised contribution from photospheric albedo photons4,5. We further consider how much this calibration error may affect interpretation of the Intercosmos results in terms of flare particles and suggest how further theoretical work, combined with results from a laboratory calibrated polarimeter, can yield information on the spatial location of hard X-ray flares as well as on their true polarisation.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1

    Tindo, I. P., Ivanov, V. D., Mandel'stam, S. L., and Shuryghin, A. I., Solar Phys., 14, 204 (1970).

  2. 2

    Tindo, I. P., Ivanov, V. D., Mandel'stam, S. L., and Shuryghin, A. I., Solar Phys., 24, 429 (1972).

  3. 3

    Tindo, I. P., Ivanov, V. D., Valnicek, B., and Livshits, M. A., Solar Phys., 27, 426 (1972).

  4. 4

    Tomblin, F., Astrophys J., 171, 377 (1972).

  5. 5

    Santangelo, N., Horstman, H., and Horstman-Moretti, E., Solar Phys., 29, 143 (1973).

  6. 6

    Haug, E., Solar Phys., 25, 425 (1972).

  7. 7

    Brown, J. C., Solar Phys., 26, 441 (1972).

  8. 8

    Brown, J. C., Proc. IAU Symp. 57, Surfer's Paradise (September 1973).

  9. 9

    Brown, J. C., Solar Phys., 18, 489 (1971).

  10. 10

    Beigman, I. L., and Vainshtein, L. A., Astr. J. USSR (in the press).

  11. 11

    van de Hulst, H. C., Light Scattering by Small Particles (Wiley, New York, 1957).

  12. 12

    Chandrasekhar, S., Radiative Transfer (Oxford University Press, London, 1950).

Download references

Author information

Affiliations

  1. Department of Astronomy, University of Glasgow, Glasgow, G12 8QQ

    • J. C. BROWN
    • , A. N. MCCLYMONT
    •  & I. S. MCLEAN

Authors

  1. Search for J. C. BROWN in:

  2. Search for A. N. MCCLYMONT in:

  3. Search for I. S. MCLEAN in:

About this article

Publication history

Received

Issue Date

DOI

https://doi.org/10.1038/247448a0

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.