1. Institute of Energy and Climate Research – Plasma Physics (IEK-4), Forschungszentrum Jülich, EURATOM Association, Trilateral Euregio Cluster, D-52425 Jülich, Germany,
2. Budker Institute of Nuclear Physics (BINP), Novosibirsk 630090, Russia
3. Institute of Energy and Climate Research – Microstructure and Properties of Materials (IEK-2), Forschungszentrum Jülich, EURATOM Association, Trilateral Euregio Cluster, D-52425 Jülich, Germany