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.

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We demonstrate the spatial mapping of the spin pumping from a magnetic insulator, yttrium iron garnet (YIG), using the inverse spin Hall effect. The inverse spin Hall effect in thin Pt wires placed on a YIG film enables local detection of the spin-current emission from the insulator, revealing spatially nonuniform spin pumping at various microwave excitation frequencies. We found that the spatial variation of the spin pumping is sensitive to the wavelength of the magnons responsible for the spin pumping as well as the thickness of the magnetic insulator. These findings provide an important information for studying spintronic phenomena in metal/insulator bilayers.

We report that magnetostatic magnon transport can be controlled by local parametric excitation of short-wavelength magnons. We found that the parametrically excited magnon either enhances or suppresses the traveling magnetostatic magnons, depending on the frequency of the magnetostatic magnons. Our time-domain measurements of the magnon transport show that the change in the static magnetization due to the creation of the parametrically excited magnons is responsible for the control of the magnetostatic magnon transport. This result provides insight into magnon-based devices without complex microprocessing.

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