The University of Southampton
University of Southampton Institutional Repository

Variations in energy, flux, and brightness of pulsating aurora measured at high time resolution

Variations in energy, flux, and brightness of pulsating aurora measured at high time resolution
Variations in energy, flux, and brightness of pulsating aurora measured at high time resolution
High-resolution multispectral optical and incoherent scatter radar data are used to study the variability of pulsating aurora. Two events have been analysed, and the data combined with electron transport and ion chemistry modelling provide estimates of the energy and energy flux during both the ON and OFF periods of the pulsations. Both the energy and energy flux are found to be reduced during each OFF period compared with the ON period, and the estimates indicate that it is the number flux of foremost higher-energy electrons that is reduced. The energies are found never to drop below a few kilo-electronvolts during the OFF periods for these events. The high-resolution optical data show the occurrence of dips in brightness below the diffuse background level immediately after the ON period has ended. Each dip lasts for about a second, with a reduction in brightness of up to 70 % before the intensity increases to a steady background level again. A different kind of variation is also detected in the OFF period emissions during the second event, where a slower decrease in the background diffuse emission is seen with its brightness minimum just before the ON period, for a series of pulsations. Since the dips in the emission level during OFF are dependent on the switching between ON and OFF, this could indicate a common mechanism for the precipitation during the ON and OFF phases. A statistical analysis of brightness rise, fall, and ON times for the pulsations is also performed. It is found that the pulsations are often asymmetric, with either a slower increase of brightness or a slower fall.
Ionosphere (auroral ionosphere; particle precipitation), Magnetospheric physics (magnetosphere-ionosphere interactions)
0992-7689
493-503
Dahlgren, Hanna
1ecbe571-901a-40db-8376-8ba72420c1dd
Lanchester, Betty S.
e864533e-eea0-471f-a3f9-7c70c25be55b
Ivchenko, Nickolay
99752978-8a44-4c2e-8c4a-984575a88f8f
Whiter, Daniel K.
9a30d7b6-ea41-44fb-bd52-3ff1964eca5c
Dahlgren, Hanna
1ecbe571-901a-40db-8376-8ba72420c1dd
Lanchester, Betty S.
e864533e-eea0-471f-a3f9-7c70c25be55b
Ivchenko, Nickolay
99752978-8a44-4c2e-8c4a-984575a88f8f
Whiter, Daniel K.
9a30d7b6-ea41-44fb-bd52-3ff1964eca5c

Dahlgren, Hanna, Lanchester, Betty S., Ivchenko, Nickolay and Whiter, Daniel K. (2017) Variations in energy, flux, and brightness of pulsating aurora measured at high time resolution Annales Geophysicae, 35, pp. 493-503.

Record type: Article

Abstract

High-resolution multispectral optical and incoherent scatter radar data are used to study the variability of pulsating aurora. Two events have been analysed, and the data combined with electron transport and ion chemistry modelling provide estimates of the energy and energy flux during both the ON and OFF periods of the pulsations. Both the energy and energy flux are found to be reduced during each OFF period compared with the ON period, and the estimates indicate that it is the number flux of foremost higher-energy electrons that is reduced. The energies are found never to drop below a few kilo-electronvolts during the OFF periods for these events. The high-resolution optical data show the occurrence of dips in brightness below the diffuse background level immediately after the ON period has ended. Each dip lasts for about a second, with a reduction in brightness of up to 70 % before the intensity increases to a steady background level again. A different kind of variation is also detected in the OFF period emissions during the second event, where a slower decrease in the background diffuse emission is seen with its brightness minimum just before the ON period, for a series of pulsations. Since the dips in the emission level during OFF are dependent on the switching between ON and OFF, this could indicate a common mechanism for the precipitation during the ON and OFF phases. A statistical analysis of brightness rise, fall, and ON times for the pulsations is also performed. It is found that the pulsations are often asymmetric, with either a slower increase of brightness or a slower fall.

Text angeo-35-493-2017 - Version of Record
Available under License Creative Commons Attribution.
Download (4MB)

More information

Accepted/In Press date: 8 March 2017
e-pub ahead of print date: 28 March 2017
Keywords: Ionosphere (auroral ionosphere; particle precipitation), Magnetospheric physics (magnetosphere-ionosphere interactions)
Organisations: Physics & Astronomy

Identifiers

Local EPrints ID: 407354
URI: http://eprints.soton.ac.uk/id/eprint/407354
ISSN: 0992-7689
PURE UUID: 3f9499ec-100e-4372-829c-8f736daa67fb
ORCID for Daniel K. Whiter: ORCID iD orcid.org/0000-0001-7130-232X

Catalogue record

Date deposited: 04 Apr 2017 01:05
Last modified: 31 Oct 2017 23:43

Export record

Contributors

Author: Hanna Dahlgren
Author: Betty S. Lanchester
Author: Nickolay Ivchenko
Author: Daniel K. Whiter ORCID iD

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×