Spiral Waves in a Lattice Array of Josephson Junction Chaotic Oscillators with Flux Effects

Josephson junction devices play a significant role in various physical nonlinear systems because of their complex characteristics. Chaotic phenomenon in various types of Josephson junction devices has been widely reported, but many of those literature studies exempted the analysis into multistability and megastability features of the device. In this work, we investigate the network behaviour using a type of Josephson junction-memristor (JJM) device considering the feedback flux effects while modelling. We have considered both AC- and DC-type external excitation currents, and while considering the AC excitation, the system shows megastability (Ramakrishnan et al. 2020). When analysing the lattice layer network constructed with JJM excited by DC bias current, the network shows a turbulent behaviour thus forming spiral waves. This was not the case when we applied AC bias current for which the network showed a much pattern-like formation confirming localised areas of energy distribution. This energy distribution is due to the homogeneous states of the local nodes which are correlated by the respective periodicity plots. When we apply AC bias current with very low frequency, the network shows small areas of local spirals which are soon dissipated by the inhomogeneous nodes nearby. Thus, we could show that the external bias current plays an important role in the collective performance of the Josephson junction devices.

Automated summary

Josephson junction-memristor (JJM) devices play a crucial role in physical nonlinear systems due to their complex characteristics. This study investigated the network behavior of JJM devices, considering both AC- and DC-type external excitation currents. The system exhibited megastability under AC excitation and formed spiral waves when excited by DC bias current, showcasing the impact of external bias currents on the collective performance of Josephson junction devices.