WP5 - STEREO/HI CIR Catalogue

Introduction:

The primary goal of WP5 is to provide a catalogue of the spatial and temporal evolution of CIRs observed by HI (and their substructures) in 3-D, following their complete formation process using different observations (mainly imaging but also insitu) from the Sun out to 1 AU. The output of the solar wind stream advanced catalogue will be optimized to help the space physics community in the search for clues on the origin, propagation, 3D morphology, and the planetary effects of CIRs and the slow solar wind. The delivery of these advanced catalogues will enhance forefront research on: the 3-D structure of CIRs; their associated pressure ridges and shocks; the origin and nature of the variability of the slow solar wind; the time-dependent evolution of high-speed streams. This resource will also be useful for future missions (e.g. ESA’s Solar Orbiter).

The work package consists of four tasks.

  • Cataloguing the occurrence of CIRs
  • Deriving/cataloguing the kinematic variation of CIRs
  • Comparing back-projected CIR tracks with coronal sources
  • Comparing forward-projected CIR tracks with in-situ measurements

Methodology:

The work package will construct a community-oriented catalogue of CIRs observed by STEREO/HI, with their main parameters, from 2007 to 2015 (minimum through maximum and early declining phase of solar cycle 24). The aim is to derive the 3-D trajectories and kinematic properties of CIRs using fitting procedures and to compare the back-projected results of CIR evolution with solar source observations; to determine the time-dependent effects of the dynamic streamer belt and of coronal holes. This activity will also compare the forward projected results of the fitting procedure with in-situ measurements of CIRs and the transient slow solar wind.

Task 1: Cataloguing the occurrence of CIRs

Using J-maps and optimized running-difference images, we will list the times of observations of each CIR in HI images, measure their latitudinal extent, measure the number of small-scale transients entrained inside each CIR for each latitudinal band, determine the minimum and maximum radial distance at which CIR are observed, and establish a common timeline (first order catalogue) of remote-sensing and in-situ measurements of CIRs. From the CIR fitted trajectories, we will provide a catalogue of the arrival times of CIRs at Mercury, Venus, Mars, Earth, Saturn, thereby providing support to European-funded space missions around these planets.

Task 2: Deriving/cataloguing the kinematic variation of CIRs

We will fit the leading edge of each CIR in HI J-maps derived at all available latitudes to obtain the spatial/temporal evolution of each CIR over ~180o longitude and ~90o latitude. When the STEREO-A and B HI fields of view overlap, we will compare the estimated location of the CIR leading edge from both spacecraft. We will fit the kinematic evolution of each transient entrained inside CIRs at all latitudes, using different fitting techniques, which will provide another estimate of the CIR location as a function of time. For small-scale transients identified simultaneously in STEREO-A/HI and STEREO-B/HI, we will use triangulation techniques to detect potential speed variations near the Sun. This catalogue will be useful to determine the kinematic properties of the slow-solar wind in the upper corona.

Task 3: Comparing back-projected CIR tracks with coronal sources

Using the derived trajectories and kinematic properties of CIRs and their small-scale transients, we will determine for each CIR observed in white-light images if there is an associated coronal hole observed in EUV. We will create a catalogue of these identified coronal holes by combining EUV images from STEREO and SDO images with potential field source surface calculations based on HMI and GONG magnetograms. This catalogue will enable scientists to study the time-dependent evolution of coronal holes with direct space-weather applications. Using trajectories of small-scale transients derived from HI we will determine the portions in the streamer belt that generate small-scale transients and compare these locations of continually updated magnetograms.

Task 4: Comparing forward-projected CIR tracks with in-situ measurements

We will track small-scale transients to 1 AU and make a list of predicted impacts at points in the heliosphere where in-situ measurements are taken. We will catalogue the in-situ properties of each small-scale transient. This latter catalogue will enable scientists to study the origin and variability of the slow solar wind. Instruments used: STEREO SECCHI/in situ, Wind, ACE, Venus Express, Ulysses where/when solar wind data is available. Role of participants: UPS: list small-scale transients that hit a spacecraft, UH: analysis of in-situ data in order to catalogue the in-situ properties of each small transient.

Deliverables:

Deliverable Number Deliverable Title Leader Delivery Month
D5.1 Establishing an online CIR catalogue UPS 12
D5.2 Fitting the leading edge of CIRs and determination of latitudinal extent UPS 24
D5.3 Catalogue of CIRs/coronal holes UPS 36
D5.4 Imagery/in situ comparison UPS 36
D5.5 Analysis of in situ data UH 36

Other Outputs:

Description of work package.

Schedule:

Description of work package.



Current Status:

Description of work package.