Edge Localized Modes (ELMs) are short breakdowns of the high confine- ment regime (H-mode) which is envis- aged to be used in power producing tokamaks (1). Due to the high power fluxes associated with them, ELMs pose demands on the design of plasma facing components. Apart from the in- terest in thermonuclear oriented plas- mas the physics of ELMs suggests fas- cinating analogies with all those explo- sive phenomena in nature accompained by rapid particles and large amounts of energies expulsion as observed for example on solar flares (2) or magnetic substorms (3). Present theories on ELM formation and dynamics suggest that they originate from a combi- nation of pressure gradient driven MHD modes (balloning) and edge current density gradient driven modes (peeling modes) which combine in creating intermediate mode number structures (n � 10 15) well localized in the plane perpendicular to the guiding magnetic field but ex- tended along the field lines (4, 5). These structures are then found to propagate in the Scrape Off Layer (SOL) where they have been measured using Langmuir probes (6, 7), magnetic pick- up coils (4) or gas puff imaging (8). In this contribution we present results on simultaneous investigations of electric and magnetic fluctuations in ASDEX Upgrade SOL plasma by means of a probe head combining Langmuir