Measurements of geomagnetic field H, D and Z components, with sampling frequency of 500 Hz, performed at TNB for the study of Shuman resonance.

The station is composed by three induction detectors oriented in the reference system HDZ. The H detector is placed along the magnetic meridian (magnetic N-S); the D detector is perpendicular to the H detector (magnetic E-W); the Z detector is aligned in the measurement place apparent vertical direction.

The magnetic declination mean value was 137 degrees during the time of measurements. Due to the observatory closeness to the polar cusp (80.0 S, 307.7 E) we can observe several phenomena related to the Earth's ionosphere cavity resonance modes (Shumann resonance) and to the IAR (Ionospheric Alfven Resonator) resonance modes caused by high energy protons injection in the polar ionosphere.