Low-frequency Electric Field Measurements Research Articles

Theoretical study on Stark effect of Rydberg atom in super low frequency electric field measurement

AbstractSuper low frequency electric field measurements are crucial in analysing electromagnetic compatibility, assessing equipment status, and other related fields. Rydberg atom‐based super low frequency electric field measurements are performed by observing the Stark shift in the spectrum of the Rydberg state. In a specific range of field strength (E < Eavoid, where Eavoid is the threshold to avoid crossing electric fields), the Rydberg atomic spectrum experiences a quadratic frequency shift in relation to the field strength, with the coefficient being determined by the atomic polarisability α. The authors establish a dynamic equation for the interaction between the external electric field and the atomic system, and present the Stark structure diagram of the Caesium Rydberg atom. The mathematical formulae for α and Eavoid in different Rydberg states are also obtained: α = A × (n*)6 + B × (n*)7 and Eavoid = C/(n*)5 + D/(n*)7, where A(B) = 2.2503 × 10−9(7.49,948 × 10−11) and C(D) = 1.68,868 × 108(2.45,991 × 109). The error of α and Eavoid compared with the experimental values does not exceed 8% and is even lower in the low Rydberg states. Accurately calculating the values of α and Eavoid is crucial in incorporating the Rydberg atom quantum coherence effect into super low frequency electric field measurements in new power systems.

Forbidden Transitions of LiI in Laser-Induced Fluorescence Spectroscopy for the Measurement of Low-Frequency Electric Fields in Plasmas

Three forbidden transition (42P-22P, 42D-32D and 22P-42F) due to the Stark effect in the LiI energy system were theoretically investigated for the measurement of low-frequency electric fields in plasmas. Numerical results concerning the intensities of the forbidden transitions and the polarization characteristics are presented in which the effect of the electron spin is taken into account. The excitation of the levels of n=4 is supposed to be possible using tunable lasers and thus, the effect of laser polarization is also considered. The first two transitions (42P-22P and 42D-32D) are suitable for measuring a rather strong electric field (1 kV/cm) and can also be used to give the direction of the electric field in plasmas. The third transition is applicable to a weak-field measurement down to about 0.1 kV/cm.

Instrumentation for DC and Low-Frequency Electric-Field Measurements on ISEE-A

The double-probe floating-potential technique is applied using long-wire antenna-probes with an effective electric-field baseline of 179 meters. 14-bit A/D conversion is used for the prime dc-field measurements. An 8-channel spectrometer is used for ac-field measurements over the range 0.19 to 1900 Hz.