Abstract
In recent UVCS/SOHO White Light Channel (WLC) observations we found quasi-periodic variations in the polarized brightness (pB) in the polar coronal holes at heliocentric distances of 1.9 to 2.45 solar radii. The motivation for the observation is the 2.5D MHD model of solar wind acceleration by nonlinear waves, that predicts compressive fluctuations in coronal holes. In February 1998 we performed new observations using the UVCS/WLC in the coronal hole and obtained additional data. The new data corroborate our earlier findings with higher statistical significance. The new longer observations show that the power spectrum peaks in the 10–12 minute range. These timescales agree with EIT observations of brightness fluctuations in polar plumes. We performed preliminary LASCO/C2 observations in an effort to further establish the coronal origin of the fluctuations.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
DeForest, C. E., and J. B. Gurman: 1998, Astrophys. J., 501, L217.
Kohl, J. L. et al.: 1995, Sol. Phys., 162, 313.
Kohl, J. L. et al.: 1997, Sol. Phys., 175, 613.
Ofman, L., Davila, J. M.: 1997a, Astrophys. J., 476, 357.
Ofman, L., Davila, J. M.: 1997b, Astrophys. J., 476, L51.
Ofman, L., Davila, J. M.: 1998, J. Geophys. Res., 103, 23677.
Ofman, L., Romoli, M., Poletto, G., Noci G., Kohl, J. L.: 1997, Astrophys. J., 491, L111.
Ofman, L., Romoli, M., Poletto, G., Noci G., Kohl, J. L.: 1998, Astrophys. J., 507, L189.
Ofman, L., Nakariakov, V., and DeForest, C. E.: 1999, Astrophys. J., in press.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1999 Springer Science+Business Media Dordrecht
About this chapter
Cite this chapter
Ofman, L. et al. (1999). SOHO Observations of Density Fluctuations in Coronal Holes. In: Kohl, J.L., Cranmer, S.R. (eds) Coronal Holes and Solar Wind Acceleration. Springer, Dordrecht. https://doi.org/10.1007/978-94-015-9167-6_46
Download citation
DOI: https://doi.org/10.1007/978-94-015-9167-6_46
Publisher Name: Springer, Dordrecht
Print ISBN: 978-90-481-5267-4
Online ISBN: 978-94-015-9167-6
eBook Packages: Springer Book Archive