Abstract
A relationship between the heliospheric magnetic field, atmospheric electric field, lightning activity, and secondary cosmic rays measured on the high mount of LomnickATIN SMALL LETTER Y WITH ACUTE Stit (2,634 m a.s.l.), Slovakia, during the declining phase of the solar cycle 24 is investigated with a focus on variations related to solar rotation (about 27 days). The secondary cosmic rays are detected using a neutron monitor and the detector system SEVAN, which distinguishes between different particles and energies.
Using spectral analysis, we found distinct similar to 27-day periodicities in variations of B-x and B-y components of the heliospheric magnetic field and in pressure-corrected measurements of secondary cosmic rays. The 27-day variations of secondary cosmic rays, on average, advanced and lagged the variations of B-x and B-y components by about 40 degrees and -140 degrees, respectively.
Distinct 27-day periodicities were found both in the neutron monitor and the SEVAN upper and middle detector measurements. A nondominant periodicity of similar to 27 days was also found for lightning activity.
A cross-spectral analysis between fluctuation of the lightning activity and fluctuation of the heliospheric magnetic field (HMF) showed that fluctuation of the lightning activity was in phase and in antiphase with B-x and B-y components of the HMF, respectively, which is in agreement with previous studies investigating the influence of solar activity on lightning. On the other hand, the similar to 27-day periodicity was not significant in the atmospheric electric field measured in Slovakia and Czechia.
Therefore, no substantial influence of B-x and B-y on the atmospheric electric field was observed at these middle-latitude stations.