Electron acceleration and relativistic proton production at the Sun in the October-November 2003 solar events

Several large solar flares occurred in October-November 2003 in an active region 0486 south of the solar equator, in particular, the flares on 28 October (S16, E08, 4B/X17.2), 29 October (S15, W02, 2B/X10.0), and on 2 November (S14, W56, 2B/X8.3). They were accompanied by the eruptions of filaments and rapid halo-type coronal mass ejections (CMEs). Large particle fluxes were detected up to relativistic energies at 1 AU. In this paper the accelerated particles and plasma structures in the corona are traced using radio, EUV and visible light observations, together with the data of neutron monitor measurements at the Earth's surface (a worldwide network of neutron monitors). We use the bulk of radio emission at decimetric and longer waves to study acceleration in the corona and the escape of suprathermal electrons and relativistic protons from the Sun. There is a delay with respect to the hard X-ray emission. But despite the delay and the association with a flare near the central meridian, the neutron monitor time profile was impulsive in the Ground Level Enhancement (GLE) of 28 October. Moreover, a prompt (PC) and delayed (DC) components in relativistic proton fluxes were distinguished in this GLE and their energy spectra above 1 GV have been derived by modeling technique from the data of 30 ground-based neutron monitors. The spectra may be indicative of multi-step (multi-source) acceleration at/near the Sun (in the corona). It is shown that the escape of the relativistic protons occurred in time coincident both with a coronal shock wave, which may be a bow shock of the CME, and with radio sources, which trace electron acceleration and magnetic field reconfiguration in the western hemisphere. Several observations support the idea that the relativistic protons were accelerated during this reconfiguration, at heights between 0.1-1.0 solar radius above the photosphere..