RESUMO
We present an alternative method for generating start electrons for time of flight (TOF) space plasma analyzers. The technique presented here takes advantage of the processes occurring during the scattering of the particles off a surface, i.e., kinetic electron emission. The use of a thin microchannel plate as a scattering surface allows us to distribute this surface along a single plane normal to the particle velocity. The uncertainty on the TOF distance is thus minimized, allowing a greater mass resolution. The first tests carried out showed that a mass resolution of 10 for a beam energy of 10 keV is easily reachable.
RESUMO
The magnetometer and electron reflectometer investigation (MAG/ER) on the Mars Global Surveyor spacecraft has obtained magnetic field and plasma observations throughout the near-Mars environment, from beyond the influence of Mars to just above the surface (at an altitude of approximately 100 kilometers). The solar wind interaction with Mars is in many ways similar to that at Venus and at an active comet, that is, primarily an ionospheric-atmospheric interaction. No significant planetary magnetic field of global scale has been detected to date (<2 x 10(21) Gauss-cubic centimeter), but here the discovery of multiple magnetic anomalies of small spatial scale in the crust of Mars is reported.