Disclosed is a magnetic-fluid momentum sphere, which is used for satellite attitude adjustment. The magnetic-fluid momentum sphere comprises stators and a spherical shell. The stators are classified into three groups, axes of the three groups of stators are orthogonal to each other, each group comprises two stators arranged symmetrically about the center of the spherical shell, and the inner surfaces of the stators are spherical surfaces. The spherical shell is formed by combining two hemispherical shells, the material of the spherical shell is a non-ferromagnetic material, the inner surfaces of the stators closely adhere to the outer surface of the spherical shell, there is no relative movement between the spherical shell and the inner surfaces of the stators, and the spherical shell is filled with magnetic fluid. The magnetic-fluid momentum sphere achieves a small size and mass, low costs, and small coupling among the axes.

Techniques are provided for implementing and using a travelling wave resonator, comprising planar optical waveguide including at least two stacked cores, to diminish Kerr effect in the travelling wave resonator. The travelling wave resonator may be used in a resonator optical gyroscope.

Techniques are provided for implementing and using a travelling wave resonator, comprising planar optical waveguide including at least two stacked cores, to diminish Kerr effect in the travelling wave resonator. The travelling wave resonator may be used in a resonator optical gyroscope.

Techniques are provided for implementing and using a travelling wave resonator. comprising planar optical waveguide including at least two stacked cores, to diminish Kerr effect in the travelling wave resonator. The travelling wave resonator may be used in a resonator optical gyroscope.

Techniques are provided for implementing and using a travelling wave resonator. comprising planar optical waveguide including at least two stacked cores, to diminish Kerr effect in the travelling wave resonator. The travelling wave resonator may be used in a resonator optical gyroscope.

The present disclosure includes dipole line trap system, a method for tuning a natural frequency of a dipole line trap system, and seismometer. One embodiment of the dipole line trap system may comprise a first axis unit. The first axis unit may comprise a first group of at least three cylindrical diametric magnets mounted in parallel around a first open region, and a first diamagnetic object in the first open region. In some embodiments, the first axis unit may comprise four cylindrical diametric magnets mounted in parallel around the first open region. In some embodiments, the first axis unit may have a natural frequency of less than 1 Hz.

The present disclosure includes dipole line trap system, a method for tuning a natural frequency of a dipole line trap system, and seismometer. One embodiment of the dipole line trap system may comprise a first axis unit. The first axis unit may comprise a first group of at least three cylindrical diametric magnets mounted in parallel around a first open region, and a first diamagnetic object in the first open region. In some embodiments, the first axis unit may comprise four cylindrical diametric magnets mounted in parallel around the first open region. In some embodiments, the first axis unit may have a natural frequency of less than 1 Hz.