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Proposal ID Gouttebroze_101

Date of Proposal
97/04/24

firstname
Pierre

lastname
Gouttebroze

institute
Institut d'Astrophysique spatiale

address
Universite Paris XI, bat 121, 91405 Orsay Cedex, France

email
goutte@corona.medoc-ias.u-psud.fr

phone

fax

proposal
We propose to study the propagation of p-modes in the
chromosphere-corona transition region by observing continuously
the variations of intensity and constructing
diagnostic diagrams (oscillatory power as a function of horizontal
wavenumber and frequency) from these observations.

The duration of the observations should be at least 8 hours
(and 12 or 16 hours if possible) in order to obtain the frequency
resolution necessary to distinguish the modes from each other.

The repetition rate should be about 1 image per minute in order
to study the usual "5 minute" (photospheric) and "3 minute"
(chromospheric) ranges.

Owing to this repetition rate and to the telemetry capabilities,
we propose to transmit every minute an image of 128x128 elements,
which corresponds to a rate of: 128x128x8/60=2185 bits/s
(with compression of factor 2).

To obtain a good resolution in "l" (azimutal degree), we plan
to use full sun images, summing the pixels 8x8 to reduce the
1024x1024 pixels of the image into an array of 128x128 elements
(another possibility consists of restricting the observations to
the central 512x512 pixels of the images, and summing the pixels
4x4, In this case, we slightly reduce the resolution, but extend
the diagram to higher degrees).

At first, we propose to perform this experiment with the
He II 304 A line (formed in the transition region). If
positive results are obtained, it could be extended later
to coronal lines.

inside_collab
J. P. Delaboudiniere

consortium
no

topic
Acoustic Waves

topic

title
Penetration of p-modes in the chromosphere-corona transition region


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