Exective summary

The Science of SCOPE

The SCOPE mission strategy

SCOPE in the Roadmap

SCOPE and the simulation studies

Link to Cross-Scale (ESA)

Field measurements

The motion of charged particles in the space is constrained by the electric and magnetic fields. The charged particles have several kinds of characteristics timescales, e.g., gyration period, plasma frequency, so on. The effects fields give to the charged particles, energization or acceleration, varies on the timescale relative to these characteristic timescales. Therefore, for the understanding of the *** of the space plasma, accurate measurement of electric and magnetic fields in wide-range timescales is important. The smallest electron-scale investigation of the charged particle motion and related parameters is the major objective of the SCOPE mission. Magnetic and electric fields are aimed to be in accordance with the high-resolution measurement of the plasma. More accurate and perfect three-dimensional measurement of the fields is essential to achieve the science objectives of SCOPE.

The field measurement by SCOPE covers the electric field from DC to 10MHz and magnetic field from DC to 100kHz. This performance enables to observe following phenomena in the magnetosphere; the global electric-field structure, magnetic activity or the field-line modifications, MHD waves, lower-hybrid waves, whistler waves, ion-cyclotron waves, Langmuir waves, Auroral kilometric waves, so on. On the other hand, not only the spectrum-analyzed data, but also the wave-form data of the electric and magnetic fields up to 100 kHz will be measured with very high sampling rate will be obtained by SCOPE.

Electrical probe antenna, flux-gate and search-coil magnetometers and wave spectrometers have been refined based on the matured design for previous missions. All of Scope satellites have two pairs of probe antenna extended in the spin plane. The tip-to-tip length of the antenna on the mother satellite is about 100m for accurate electric field measurement in the thin plasma. Furthermore, some techniques particular for SCOPE field measurements have been developed. Major one is the rigid antenna extended along the spin axis. It enables the three-dimensional measurement of the electric field. For the mother and three daughter satellites, it corresponds to the direction perpendicular to the ecliptic plane. Meanwhile longer antenna aligned to this direction enables more accurate measurement in the direction perpendicular to the ecliptic plane. One of the daughter satellites, so called 'near' satellite, has the spin axis aligned to the sunward direction and 60m (tip-to-tip) antenna in the spin plane.

SCOPE project needs not only the excellent performance of the field instruments, but also the optimization of the satellite system, e.g., electro-magnetic compatibility, magnetic cleanliness, satellite attitude and electric probe along the spin axis.