The DynaMICCS perspective. A mission for a complete and continuous view of the Sun dedicated to magnetism, space weather and space climate

Experimental Astronomy (Impact Factor: 1.99). 03/2009; 23(3):1017-1055. DOI: 10.1007/s10686-008-9111-z


The DynaMICCS mission is designed to probe and understand the dynamics
of crucial regions of the Sun that determine solar variability,
including the previously unexplored inner core, the radiative/convective
zone interface layers, the photosphere/chromosphere layers and the low
corona. The mission delivers data and knowledge that no other known
mission provides for understanding space weather and space climate and
for advancing stellar physics (internal dynamics) and fundamental
physics (neutrino properties, atomic physics, gravitational moments...).
The science objectives are achieved using Doppler and magnetic
measurements of the solar surface, helioseismic and coronographic
measurements, solar irradiance at different wavelengths and in-situ
measurements of plasma/energetic particles/magnetic fields. The
DynaMICCS payload uses an original concept studied by Thalès
Alenia Space in the framework of the CNES call for formation flying
missions: an external occultation of the solar light is obtained by
putting an occulter spacecraft 150 m (or more) in front of a second
spacecraft. The occulter spacecraft, a LEO platform of the mini sat
class, e.g. PROTEUS, type carries the helioseismic and irradiance
instruments and the formation flying technologies. The latter spacecraft
of the same type carries a visible and infrared coronagraph for a unique
observation of the solar corona and instrumentation for the study of the
solar wind and imagers. This mission must guarantee long (one 11-year
solar cycle) and continuous observations (duty cycle > 94%) of
signals that can be very weak (the gravity mode detection supposes the
measurement of velocity smaller than 1 mm/s). This assumes no
interruption in observation and very stable thermal conditions. The
preferred orbit therefore is the L1 orbit, which fits these requirements
very well and is also an attractive environment for the spacecraft due
to its low radiation and low perturbation (solar pressure) environment.
This mission is secured by instrumental R and D activities during the
present and coming years. Some prototypes of different instruments are
already built (GOLFNG, SDM) and the performances will be checked before
launch on the ground or in space through planned missions of CNES and

Download full-text


Available from: Sylvaine Turck-Chièze,
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: From time immemorial men have strived to measure the size of celestial bodies. Among them, the diameter of the Sun was a source of curiosity and study. Tackled by Greek astronomers from a geometric point of view, an estimate, although incorrect, has been first determined, not truly called into question for several centuries. One must wait up to the XVIIth century to get the first precise determinations made by the French school of astronomy. Gradually, as the techniques were more and more sophisticated, many other solar diameter measurements were carried out, notably in England, Germany, Italy and US. However, even with instruments at the cutting edge of progress, no absolute value of the solar diameter has been provided yet, even if the community has adopted a canonical radius of 959.″63, given in all ephemeris since the end of the XIXth century. One of the major difficulties is to define a correct solar diameter. Another issue is the possible temporal variability of the size of the Sun, as first advocated at the end of the XIXth century by the Italian school. Today, this question is just on the way to being solved in spite of considerable efforts developed on ground-based facilities or on board space experiments. We will here give a review of some of the most remarkable techniques used in the past, emphasising how incorrect measurements have driven new ideas, leading to develop new statements for the underlying physics. On such new grounds, it can be speculated that the roundness of the Sun is not perfect, but developing a thin “cantaloupe skin” in periods of higher activity, with departures from sphericity being inevitably bounded by a few kilometers (around 80 km or 10 to 15 mas).
    European Physical Journal H, The 10/2012; 37(5). DOI:10.1140/epjh/e2012-20030-4 · 1.05 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Several works have reported changes of the Sun's subsurface stratification inferred from f-mode or p-mode observations. Recently a non-homologous variation of the subsurface layers with depth and time has been deduced from f-modes. Progress on this important transition zone between the solar interior and the external part supposes a good understanding of the interplay between the different processes which contribute to this variation. This paper is the first of a series where we aim to study these layers from the theoretical point of view. For this first paper, we use solar models obtained with the CESAM code, in its classical form, and analyze the properties of the computed theoretical f-modes. We examine how a pure variation in the calibrated radius influences the subsurface structure and we show also the impact of an additional change of composition on the same layers. Then we use an inversion procedure to quantify the corresponding f-mode variation and their capacity to infer the radius variation. We deduce an estimate of the amplitude of the 11-year cyclic photospheric radius variation.
    The Astrophysical Journal 09/2008; 690(2). DOI:10.1088/0004-637X/690/2/1272 · 5.99 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Studies of the Sun-Earth relationships during the past years have dramatically changed our view on Solar-Terrestrial Physics. Neither is the interplanetary medium unstructured or quasi-static, nor is it a simple magnetic stratified object. Thus, the interaction of the solar electromagnetic radiation (photons), hot plasma (electrons, protons and other ions), cosmic rays, microscopic dust particles, and magnetic fields (primarily from the Sun) with the upper environment of our Earth leads to a complex physics which is far to be understandable. This new science is growing rapidly, as well as for the physical problems which arise as for its growing impact on our societies. This last case is well illustrated by the emergence of the so-called Space Weather. In spite of a great number of papers and books written on this subject and on a broader one devoted to Solar-Terrestrial links, the different terms deserve to be clarified. In this paper, we will first establish a clear distinction between Space Weather, Space Climate, Space Physics, Sun-Earth connections, and Helioclimatology, this last word being introduced to describe the role of the Sun in the Earth's climate forcing. In a second step, we will emphasize the key role of the ranging time on which the effects may act. We will then underline the necessity to better predict solar activity showing the physical difficulties for such an exercise, yielding the extreme complexity for forecasting specific events. The three dataset, past Earth's temperature (since AD 630), solar shape variability (since AD 1600) and strength of umbral/sunspots magnetic field (since AD 1995) lead all to a Next Grand Minima predictable for 2015-2018. We will conclude by giving some imprints for the future.
Show more