HELCATS

This WP provides the foundation for this project (including scientific coordination), namely the production of a catalogue of CMEs in the heliosphere. The catalogue will be produced from manual inspection of STEREO/HI data but use of automated techniques will be investigated. Comparisons with coronal CME catalogues will be made.

The work package consists of four tasks.

• Manual cataloguing of STEREO/HI CMEs
• Automatic cataloguing of STEREO/HI CMEs
• Comparison of CME catalogues
• Scientific management

This activity is based on the analysis of the Heliospheric Imager data from the instruments on the two NASA spacecraft that constitute the STEREO (Solar TErrestrial RElations Observatory) mission.

Task 1: Manual cataloguing of STEREO/HI CMEs

Each STEREO/HI instrument has detected many hundreds of CMEs in the heliosphere since the start of the science phase of the mission in April 2007 (e.g. Harrison et al. 2009; 2012). In Task 1, we will, via visual inspection of the HI-1 images from the two spacecraft independantly, catalogue these CMEs in terms of their basic observational parameters: observing spacecraft; entry time into the HI-1 field of view; position angle corresponding to the central axis of propagation; position angle span. We will also indicate potential halo CMEs - where the CME is directed towards the observing spacecraft. In these situations, a CME‘s central position angle and span cannot be unambiguously determined; such CMEs are of particular interest in terms of comparison with in-situ measurements. This process will be continued throughout as new observations are made.

Task 2: Automatic cataloguing of STEREO/HI CMEs

While in Task 1 CMEs are identified manually by visual inspection, in Task 2 we investigate the possibility of the automatic detection of CMEs in the heliosphere from STEREO/HI-1 images. This has never been tried before, so a successful result would contribute greatly to the advancement in the analysis of HI data, and to CME research in general. This task will be founded on the vast expertise that has been built up by the team at ROB in the autonomous detection of CMEs in coronagraph images from the SOHO/LASCO instrument and, more recently, from STEREO/COR2 (e.g. Robbrecht et al. 2009). Should this assessment prove successful, the observational parameters of the automatically-detected CMEs will be catalogued in an analogous manner to those detected manually in Task 1 above.

Task 3: Comparison of CME catalogues

In Task 3, we will asses the outputs from Tasks 1 and 2 in a number of ways: As the mission has progressed, the degree of overlap between the fields-of-view of the HI instruments on the two STEREO spacecraft has evolved. In Task 3, we will reconcile the CME catalogues that are produced separately for the two STEREO spacecraft (in Task 1 and, potentially, Task 2). The information in the CME catalogues will be augmented to reflect the fact that some of the CMEs will have been detected simultaneously from the vantage points of STEREO-A and STEREO-B. We will also compare the manually and automatically-generated catalogues, not least to assess the success of the later. This analysis will be performed both on a case-by-case basis and in terms of the overall statistical properties of CMEs. Note that should the automatic detection of CMEs in HI-1 prove untenable, the reasons why will be assessed to investigate potential improvements to the processing of the HI data steam itself. The CME catalogues generated in Tasks 1 and 2 above will be compared to pre-existing manually and automatically generated CME catalogues derived from coronal imaging observations (primarily from SOHO/LASCO and STEREO/COR2 coronagraph observations), again on a case-by-case basis and statistically. Some of these catalogues have been created under the auspices of previous FP7 projects (the SOTERIA COR2 CME list in particular). The catalogues created in WP2 will be used as a basis for the work that forms WP3 and WP4.

Task 4: Scientific management

This task involves the scientific management of the HELCATS project. Regular operations will include monthly teleconferences, bi-annual project meetings, and annual science meetings, as defined in the management plan. Through these meetings the WP leader will coordinate the scientific discussion, planning and reporting of the project.

Description of work package.

Description of work package.

Description of work package.