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INSTITUTET FÖR RYMDFYSIK UPPSALA
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Swedish Institute of Space Physics (59o50.272'N, 17o38.786'E)
Student project at IRF Uppsala

Project work (30 c)/ Examensarbete (30 hp)

Cluster EFW Internal Burst Data

Student: Johan Reponen, Luleå University of Technology
Supervisor: Yuri Khotyaintsev
Period: Autumn 2010

Background

ESA's Cluster mission consists of four identical spacecraft flying in formation high above the Earth's poles, launched into space in 2000. Due to its success, the original two-year mission has been extended several times, first through 2005 and then through 2009, and 2010. Cluster is part of an international collaboration to investigate the physical connection between the Sun and Earth. Flying in a tetrahedral (triangular pyramid) formation, the four spacecraft collect the most detailed data yet on small-scale changes in near-Earth space and the interaction between the charged particles of the solar wind and Earth's atmosphere. This will enable scientists to build a three-dimensional model of the magnetosphere and to better understand the processes taking place inside it. The Space Plasma Physics Research Program at the Swedish Institute of Space Physics is responsible for the Electric Field and Wave (EFW) instrument on Cluster, including delivery of high quality calibrated scientific data to the Cluster Active Archive (http://caa.stec.esa.int). While most of the EFW products are already delivered, the EFW internal burst, which is a set of high resolution snapshots of electric field, still requires more work in order to reach the required high quality.

Project

The internal burst data from the EFW instrument on the Cluster mission have great potential but needs some processing before becoming a part of the Cluster Active Archive (CAA), where all other viable from the mission are stored. The aim fo this thesis was to create a program that can correct large quantitites of internal burst data, plot the data comparing it to the normal mode data, and save the results. Previously the data ave been corrected on a case-to-case basis. Ther is also a detailed description on how the program corrects and plots tha data, and saves these plots in a database. Matlab is used for the data correction and plotting of the results.

An EFW internal burst (IB) is collected two times per orbit. The burst collection is triggered by high electric field activity and represents a very valuable scientific dataset, as it is the highest time resolution electric field series available on Cluster. The project aim was to design and implement algorithms for the known problems with the IB data, produce summary plots for the entire mission and study occurrence of the IBs. It also included a survey of where the burst data had been taken. The work performed included:

  • Introduction to EFW instrument and data processing chain
  • Design and implement of new algorithms for the IB production
  • Production of summary plot database and a statistical study of burts occurrence
  • Report writing and seminar presentation

Results

Project report [PDF, 1.2 MB]

[EFW internal burst example]
Example of EFW internal burst data sampled at 9 ksamples/s. From Tjulin et al., Lower hybrid cavities in the inner magnetosphere, Geophys. Res. Lett., 30, 1367, doi:10.1029/2003GL016915 (2003).

http://www.space.irfu.se/exjobb/2010_johan_reponen/index.html
last modified on Tuesday, 13-Sep-2011 14:32:41 CEST