Seeing the corona with the solar probe plus mission: the wide-field imager for solar probe+ (WISPR)

Abstract

The Solar Probe Plus (SPP) mission scheduled for launch in 2018, will orbit between the Sun and Venus with diminishing perihelia reaching as close as 7 million km (9.86 solar radii) from Sun center. In addition to a suite of in-situ probes for the magnetic field, plasma, and energetic particles, SPP will be equipped with an imager. The Wide-field Imager for the Solar PRobe+ (WISPR), with a 95º radial by 58º transverse field of view, will image the fine-scale coronal structure of the corona, derive the 3D structure of the large-scale corona, and determine whether a dust-free zone exists near the Sun. Given the tight mass constrains of the mission, WISPR incorporates an efficient design of two widefield telescopes and their associated focal plane arrays based on novel large-format (2kx2k) APS CMOS detectors into the smallest heliospheric imaging package to date. The flexible control electronics allow WISPR to collect individual images at cadences up to 1 second at perihelion or sum several of them to increase the signal-to-noise during the outbound part of the orbit. The use of two telescopes minimizes the risk of dust damage which may be considerable close to the Sun. The dependency of the Thomson scattering emission of the corona on the imaging geometry dictates that WISPR will be very sensitive to the emission from plasma close to the spacecraft in contrast to the situation for imaging from Earth orbit. WISPR will be the first 'local' imager providing a crucial link between the large scale corona and the in-situ measurements.

Asymmetric expansion of coronal mass ejections in the low corona

“…Opposite to the early general belief that CMEs were spherical bubbles holding rotational symmetry (e.g., Crifo et al 1983) supported by observations of Earth-directed circular halo CMEs (e.g., Howard et al 1982), a number of studies have indicated that many CMEs (if not all, see Vourlidas et al 2013) are organized along a major axis. Moreover, they present a topology consistent with that of a twisted magnetic flux rope in agreement with in situ detections of MCs.…”

Solar Wind Electrons Alphas and Protons (SWEAP) Science Operations Center initial design and implementation

“…Solar Wind Electrons Alphas and Protons (SWEAP) Suite will measure the thermal plasma that constitutes the bulk of the solar wind. The Wide-field Imager for Solar Probe Plus [3] (WISPR), is a white light imager that will image the heliosphere that the spacecraft will fly through. In addition, there is an SPP observatory scientist that serves as a liaison between the broader scientific community and the mission's Science Working Group (SWG).…”

The Solar Mass Ejection Imager (SMEI) Space Experiment

“…Heliospheric imagers very similar to the STEREO/HIs are currently being developed for the next generation of solar spacecraft observatories (SoloHI for Solar Orbiter [84] and WISPR for Solar Probe Plus [85]) that are scheduled for launch near the end of the decade. In addition, other more general concepts and guidelines have been proposed for possible future missions [86].…”