STORMS produces advanced catalogues of solar/heliospheric structures. The production of these catalogues is based on the detailed analysis of remote-sensing observations and in situ data. They can involve multi-point imaging to derive the 3-D structure of solar wind structures. They can also be produced from the output of simulations of the solar corona and solar wind.
Catalogues of 3D Shock Waves
To test the shock hypothesis as the prime particle accelerator in the heliosphere, it is essential the further development and the application of novel methods to determine the shock wave dynamics during solar eruptive events. We exploit coronal imagery in different vantage points and wavelengths to locate and map the time varying 3-D expansion of pressure waves and derive their magneto-plasma properties including: the velocity, Mach numbers, compression ratios and geometry in 3-D. Our methods, _that constitute the current state-of-the-art_, reside in forward shock modeling techniques using nearly simultaneous multi-viewpoint white light and EUV observations of pressure/shock waves combined with background coronal and solar wind MHD models to deduce the critical shock parameters in 3-D. The application of the developed tools and methods during COROSHOCK project allow us to perform:
- Detailed 3-D reconstructions and modeling of coronal shock waves.
- Detailed coupling of the shock wave modelling with magnetic connectivity to evaluate the shock impact on specific regions of the inner heliosphere.
- Detailed analysis of the 3D shock wave properties and connection to SEP and γ-ray events properties.
- [Under-development] The construction of catalog of 3-D reconstructed and modeled shock waves for a plethora of eruptive events.
The systematic monitoring of the solar wind in high-cadence and high-resolution heliospheric images taken by the Solar-Terrestrial Relation Observatory (STEREO) spacecraft permits the study of the spatial and temporal evolution of variable solar wind flows from the Sun out to 1 AU, and beyond. To track individual features as they propagate through the fields of view of the heliospheric imagers, maps of brightness variation are often created by extracting bands of pixels along a constant position angle (PA), corresponding to a fixed solar radial, and displaying them as a function of elongation (Y-axis) and time (X-axis). Such time–elongation maps are often referred to as J-maps (Sheeley et al., 1999, 2008a,b; Davies et al., 2009).
We have derived the spatial-temporal evolution of each of these corotating interaction regions ((CIRs; reviewed in, e.g., Owens & Forsyth 2013) ) by using a well-established fitting technique. As part of the EU Framework 7 (FP7) Heliospheric Cataloguing, Analysis and Techniques Service (HELCATS) project, we have generated a catalog listing the properties CIRs well-observed in images taken by the Heliospheric Imager (HI) instruments onboard STEREO-A and STEREO-B between 2007 and 2014. This catalogue provides:
- A publicly available list of CIRs/SIRs observed in Heliospheric Imaging from April 2007 to September 2014 (more than 200 events). Available through HELCATS website or interactively through the Propagation Tool. User-defined fitting can be also performed instead of the provided fit.
- Corresponding mean velocity of each structure, origin point on the solar surface, and predicted impact times at different vantage points in the inner heliosphere.
- Possibility to directly compare the predicted impact time with in-situ measurement, through the interface of the Propagation Tool with AMDA database.
- Detailed list of individual blobs for one representative case. Study presented in Sanchez-Diaz et al, 2017. Fiiting data of blobs available on demand.
- Plotnikov et al, Solar Physics, Volume 291, Issue 6, pp.1853-1875 (2016)
- Sanchez-Diaz et al, Astrophysical Journal Letters, Volume 835, Issue 1, article id. L7, 7 pp. (2017)
- Sanchez-Diaz et al, Astrophysical Journal, Volume 851, Issue 1, article id. 32, 17 pp. (2017)
- Sanchez-Diaz et al, Astrophysical Journal, Volume 852, Issue 1, article id. 51, 11 pp. (2019)
Catalogues of CIRs
We account for the physical processes known to operate in the corona and in the interplanetary medium during the acceleration and transport of particles. The production of high-energy particles at the shock will be parameterized using the magneto-plasma shock parameters that are deduced from the 3-D reconstructions and modeling. The result of this parameterization will produce a time varying spectrum of particles at the shock. In addition, we will account for particle transport mechanisms in the interplanetary medium by developing a 3-D particle transport model based on the solution of stochastic differential equations to model the random walk of energetic particles during their propagation to 1AU. This approach is computationally tractable and much simpler to implement numerically than the solution of the full Parker transport equation using finite-difference schemes.
From the application of the acceleration and transport models to the modeled shock waves we will:
- Parameterise the particle energisation and modell particle propagation from the shock to the solar surface to explain the properties of the long-duration >100 MeV γ-ray events.
- Be able to study the longitudinal variability of SEPs through the coupled shock wave and particle transport modeling.
- Exploit the possibility to convert the flux of energetic particles into electromagnetic radiation to produce synthetic γ-ray, hard X-ray, and radio fluxes during highly energetic eruptive events.