No CrossRef data available.
We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
Published online by Cambridge University Press: 17 November 2003
We analyse observations of the helium lines obtained with CDS onboard SOHO. The He i 584.3 Å/O iii intensity ratio shows a lower limit and an upper limit that decrease with increasing O iii intensity. At low O iii intensities this ratio increases significantly. An upper limit arises naturally if the enhancement mechanism involves turbulent motions transporting the helium atoms and ions through the steep transition region temperature gradient. The He i 537.0-Å/He i 584.3-Å and He ii 303.8-Å/He i 584.3-Å intensity ratios both decrease as the He i 584.3-Å line intensity increases. The values of the line ratios support the enhancement of the helium lines by turbulent motions, but appear to rule out the enhancement due to excitation by non-thermal coronal electrons.
To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Dropbox account. Find out more about saving content to Dropbox.
To save this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Google Drive account. Find out more about saving content to Google Drive.