Instrument

SPICE

EUI HRI

EUI FSI

STIX

PHI

SWA

MAG

EPD

SoloHI

RPW

2.3 How and where do shocks form in the corona and in the heliosphere?

Remote sensing will provide observations of shock drivers, such as flares (location, intensity, thermal/non-thermal electron populations, time-profiles), and manifestations of CMEs (waves, dimmings, etc.) in the low corona with a spatial resolution of a few hundred kilometers and cadence of a few seconds.

3.1.2.1 Understand energy release and particle acceleration process

• Origin from the footprints of newly formed loops (Hurford et al., 2006).

• Acceleration relating to the magnetic reconnection process.

• Properties of flare energy release (in high spatial and temporal resolution).

3.1.2.2 Evaluate how significantly large flares contribute directly to gradual SEP events

For the magnetically well-connected 2 November 2003 and 20 January 2005 flares, the spectra inferred for the energetic protons that produce the X-ray lines observed by RHESSI are essentially the same, within measurement uncertainties, as the spectra of SEP protons at 1 AU. The extremely rapid rise of SEP fluxes at 1 AU after the 20 January 2005 flare X-ray peak raises serious questions about CME-driven shock acceleration. Measurements of SEPs close to the Sun will provide the timing and compositional information to evaluate how significantly do large flare contribute di- rectly to gradual SEP events.

3.1.2.5 X-ray prompt events

Prompt events are well correlated with the occurrence of 3He rich SEP events. However, arrival time studies of ions seen at 1 AU suggest a delayed release of the ions relative to electrons, at least when assuming scatter-free transport. This is rather puzzling as it suggests a different accelerator for electrons and ions despite the closely connected occurrence. However, electrons and ions could still be released simultaneously with propagation effects explaining the observed delays. This objective is about exploring if the comparative delay is real or due to propagation effects. It should be studied in different heliocentric distances and hopefully near the perihelion in order to better establish the nature of the flare region (with STIX & EUI). Complete set of observations is required: STIX, EUI, RPW + ground-based radio observations (good to have). That will allow studying the magnetic structures along which flare-accelerated particles escape into interplanetary space.

5.1 Additional Science Objectives of EUI.

5.1.1 

Study the corona and its phenomena in a high spatial and temporal scale (active regions during flares or in quiescent conditions, coronal holes, quiet Sun)

Whatever the active region target, the high spatial resolution of HRI is used in a mode close to A mode with a time resolution of the order of 1 sec. For the polar coronal hole mode, the high latitude is mandatory and the compression in Lalpha possibly lower than 15 (mode C). Complementary observations of SPICE in Lbeta would be very useful.