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For passive magnetic levitation a relative permeability below 1 is needed (corresponding to a negative susceptibility). Permeability varies with a magnetic field. Values shown above are approximate and valid only at the magnetic fields shown. They are given for a zero frequency; in practice, the permeability is generally a function of the ...
for virtually any well-behaved function g of dimensionless argument φ, where ω is the angular frequency (in radians per second), and k = (k x, k y, k z) is the wave vector (in radians per meter). Although the function g can be and often is a monochromatic sine wave , it does not have to be sinusoidal, or even periodic.
Its reduction with increasing frequency, as the ratio of skin depth to the wire's radius falls below about 1, is plotted in the accompanying graph, and accounts for the reduction in the telephone cable inductance with increasing frequency in the table below. The internal component of a round wire's inductance vs. the ratio of skin depth to radius.
where μ is the magnetic permeability, ε is the (real) electric permittivity and σ is the electrical conductivity of the material the wave is travelling through (corresponding to the imaginary component of the permittivity multiplied by omega). In the equation, j is the imaginary unit, and ω is the angular frequency of the wave.
As before, we are assuming the magnetic permeability, µ of both media to be equal to the permeability of free space µ 0 as is essentially true of all dielectrics at optical frequencies. Amplitude coefficients: air to glass Amplitude coefficients: glass to air. In the following equations and graphs, we adopt the following conventions.
The relative low frequency permittivity of ice is ~96 at −10.8 °C, falling to 3.15 at high frequency, which is independent of temperature. [21] It remains in the range 3.12–3.19 for frequencies between about 1 MHz and the far infrared region. [22]
Saturation is most clearly seen in the magnetization curve (also called BH curve or hysteresis curve) of a substance, as a bending to the right of the curve (see graph at right). As the H field increases, the B field approaches a maximum value asymptotically , the saturation level for the substance.
Low-frequency time domain measurements (10 −6 to 10 +3 Hz) Low-frequency frequency domain measurements (10 −5 to 10 +6 Hz) Reflective coaxial methods (10 +6 to 10 +10 Hz) Transmission coaxial method (10 +8 to 10 +11 Hz) Quasi-optical methods (10 +9 to 10 +10 Hz) Terahertz time-domain spectroscopy (10 +11 to 10 +13 Hz) Fourier-transform ...