LEMUR: Large European Module for solar Ultraviolet Research. European contribution to JAXA's Solar-C mission

Abstract

Understanding the solar outer atmosphere requires concerted, simultaneous solar observations from the visible to the vacuum ultraviolet (VUV) and soft X-rays, at high spatial resolution (between 0.1" and 0.3"), at high temporal resolution (on the order of 10 s, i.e., the time scale of chromospheric dynamics), with a wide temperature coverage (0.01 MK to 20 MK, from the chromosphere to the flaring corona), and the capability of measuring magnetic fields through spectropolarimetry at visible and near-infrared wavelengths. Simultaneous spectroscopic measurements sampling the entire temperature range are particularly important. These requirements are fulfilled by the Japanese Solar-C mission (Plan B), composed of a spacecraft in a geosynchronous orbit with a payload providing a significant improvement of imaging and spectropolarimetric capabilities in the UV, visible, and near-infrared with respect to what is available today and foreseen in the near future. The Large European Module for solar Ultraviolet Research (LEMUR), described in this paper, is a large VUV telescope feeding a scientific payload of high-resolution imaging spectrographs and cameras. LEMUR consists of two major components: a VUV solar telescope with a 30 cm diameter mirror and a focal length of 3.6 m, and a focal-plane package composed of VUV spectrometers covering six carefully chosen wavelength ranges between 17 and 127 nm. The LEMUR slit covers 280" on the Sun with 0.14" per pixel sampling. In addition, LEMUR is capable of measuring mass flows velocities (line shifts) down to 2 km/s or better. LEMUR has been proposed to ESA as the European contribution to the Solar C mission.

35 pages, 14 figures. To appear on Experimental Astronomy

References in corpus (6)

• Observing the Roots of Solar Coronal Heating - in the Chromosphere
• Magnetic Landscape of Sun's Polar Region
• Photospheric flux cancellation and associated flux rope formation and eruption
• Flows and Non-thermal Velocities in Solar Active Regions Observed with the Extreme-ultraviolet Imaging Spectrometer on Hinode: A Tracer of Active Region Sources of Heliospheric Magnetic Fields?
• Propagating MHD waves in coronal holes
• An optimization principle for the computation of MHD equilibria in the solar corona

Cited by in corpus (11)

• Solar ultraviolet bursts
• High Spatial Resolution Observations of Loops in the Solar Corona
• Non-Equilibrium Processes in the Solar Corona, Transition Region, Flares, and Solar Wind \textit{(Invited Review)}
• The coronal source of extreme-ultraviolet line profile asymmetries in solar active region outflows
• Signatures of the non-Maxwellian $\kappa$-distributions in optically thin line spectra \subtitle{I. Theory and synthetic Fe IX--XIII spectra}
• Spectroscopic Observations of Fe XVIII in Solar Active Regions
• Transition Region Abundance Measurements During Impulsive Heating Events
• Prospects of solar magnetometry - from ground and in space
• Towards a Quantitative Comparison of Magnetic Field Extrapolations and Observed Coronal Loops
• Future perspectives in solar hot plasma observations in the soft X-rays
• Pre-flare and active region plasma flows and structure seen by the short wavelength camera on SOLAR-C/EUVST