TIDE- Instrument Description

List of Figures:

Plate 1. Photograph of TIDE sensor illustrating the orientation of the seven entrance apertures with respect to the semi-cylindrical instrument package, and the layout of assemblies on the sensor baseplate.

Figure 1. Perspective view of TIDE instrument including its electronics package, showing the orientation of entrance apertures, arming plugs, thermal blankets, purge fittings, connectors, and mounting lugs.

Figure 2. Two views of the POLAR spacecraft showing TIDE and PSI pointing and mounting layout. Note that one TIDE aperture field of view is contiguous with the spin axis.1

Figure 3. Section view of the TIDE sensor with cutaways at various levels showing the placement of the START detectors and STOP detectors, as well as the angular layout of the seven channels.

Figure 4. Section view of the TIDE sensor showing the optics path through the mirror, RPA, immersion lens, UV rejection deflector, START foils, and STOP detectors for a single channel, with rays plotted for parameters which completely fill the instrument aperture in space, angle, and energy.

Figure 5. TIDE functional block diagram, showing the relationships among the principal components.

Figure 6. Geometry for a single TIDE collimator providing 22.5° wide response in polar angle. "Instrument C/L" refers to the symmetry axis of the TIDE sensor, around which the polar angle channels are arranged radially, distributed in polar angle.

Figure 7. Section view of the TIDE sensor similar to that in Figure 4, but illustrating the optics of collection of electrons emitted from the START foils by the START MCP detectors.6

Figure 8. PSI functional block diagram illustrating the relationships among the principal components.

Figure 9. Schematic illustration of PSI source, illustrating the roles of the several PSI power supplies in providing plasma emission and bias control.

Plate 2. Photograph of the PSI source assembly. Plasma is emitted from the aperture at the end of the cylindrical package.

Figure 10. PSI Gas Feed System block diagram.

Figure 11. The simulated and measured response of the TIDE instrument as a function of the ratio of Mirror to RPA potentials. The geometric factor (GF) is the product of the energy pass band (dE/E), the azimuthal response (dAz), the polar angle response (dP), and the effective area (Aeps).

Figure 12. Measured response of a TIDE aperture versus RPA voltage and azimuth angle, for a 25 eV beam.

Figure 13. TIDE mass spectral response formed by superposing the response to laboratory beams generated from four different gas leaks.

Figure 14. Unsmoothed TIDE response to a polar wind distribution (upper panel: V// = 21 km/s, T = 0.15 eV) and to a bi-Maxwellian model of an upwelling ion distribution (lower panel: T// = 3 eV, T^). Sampling resolution corresponds to the normal operating mode for TIDE in flight.

Figure 15. PSI operating parameter space illustrating the wide range of operating points which are possible. Selection of an operating point in flight is based upon minimum fluctuation in the discharge and emitted plasma current. The triangle indicates approximately the conditions at which PSI will operate on POLAR, while the circle indicates a high-current capability alternative.

Figure 16. TIDE data flow chart.

Figure 17. Geometry for the derivation of the TIDE mirror shape required to bring a parallel beam, incident from the right, to a focus at the desired point (0, f/2).

Figure 18. TOF electronics block diagrams illustrating the relationships among the principal components: the START and STOP preamplifier-discriminators, the TAC, and the logic module.

Figure 19. TIDE IMP/DP schematic block diagram.

Figure 20. PSI Electronics block diagram.