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The Low Frequency plasma wave Analyzer, LFA, on board the PLANET-B spacecraft has been developed to measure the Martian plasma waves. Two orthogonal electric dipole wire antennas, 50 m tip-to-tip, in the spacecraft spin plane are used to measure plasma waves, dc electric fields, and the spacecraft potential relative to the ambient plasma. The LFA has capability to measure the wave spectrum in the band from 10 Hz to 32 kHz, and to capture the signal waveform in the band from dc to 32 kHz by using a 4 MByte memory. The LFA scientific objectives are to explore the following: (1) Macroscopic plasma environment and boundaries from the solar wind to the ionosphere, (2) Microscopic plasma phenomena induced by the interaction between the solar wind and the Martian atmosphere and the moon Phobos, (3) Generation and propagation of electromagnetic waves, (4) Plasma densities and waves in the nightside ionosphere and tail, and (5) Comparison of Martian plasma waves with those of other planets such as non-magnetized Venus and magnetized Earth.

We apply the wave-kinetic approach to study nonlinearly coupled Rossby wave-zonal flow fluid turbulence in a two-dimensional rotating fluid. Specifically, we consider for the first time nonlinear excitations of zonal flows by a broad spectrum of Rossby wave turbulence. Short-wavelength Rossby waves are described here as a fluid of quasi-particles, and are referred to as the 'Rossbyons'. It is shown that Reynolds stresses of Rossbyons can generate large-scale zonal flows. The result should be useful in understanding the origin of large-scale planetary and near-Earth atmospheric circulations. It also provides an example of a turbulent wave background driving a coherent structure.

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