Coronal electron acceleration and relativistic proton production during the 14 July 2000 flare and CME

Abstract

Abstract. The large solar flare of 14 July 2000 10 UT occurred in an active region near the central meridian. It was accompanied by the eruption of a filament and a rapid halo-type coronal mass ejection (CME). Large particle fluxes were detected up to relativistic energies at 1 AU. In this paper accelerated particles and plasma structures in the corona are traced using radio, X-ray, EUV and visible light observations, together with neutron monitor measurements of relativistic protons at 1 AU. Both the bulk of the radio emission at decimetric and longer waves and the escape of suprathermal electrons and relativistic protons from the Sun were delayed by 10-20 min with respect to the hard X-ray emission. Despite the delay and the association with a flare near the central meridian the neutron monitor time profile was impulsive. We show that the escape of the relativistic protons occurred in time coincident both with a coronal shock wave, which may be the bow shock of the CME, and with radio sources which trace electron acceleration and magnetic field reconfiguration in the western hemisphere. Three observations support the idea that the relativistic protons were accelerated during this reconfiguration, at heights between 0.1 and 1 R above the photosphere, and not in the flaring active region or at the bow shock of the CME: (i) the rise of the neutron monitor count rates is simultaneous with the brightening of a new continuum radio source; (ii) the duration of the continuum emission is similar to the rise time of the neutron monitor count rates; (iii) the radio source is close to the Earth-connected interplanetary magnetic field line.

High-frequency slowly drifting structures in solar flares

“…The drifting pulsation-continuum structure of April 12, 2001 was accompanied by the type II burst (flare shock). This drifting structure is similar to those observed in the July 14, 2000 (Klein et al 2001) and in the April 18, 2001 flares (Hudson et al 2001). On the other hand, the remaining two drifting structures (August 18, 1998 andNovember 23, 2001) are similar to that observed in the October 5, 1992 flare (Kliem et al 2000).…”

“…The association with the highfrequency slowly drifting burst was also reported. Furthermore, Klein et al (2001) presented a radio spectrum of the July 14, 2000 flare with the slowly drifting continuum at 10:25-10:40 UT in the frequency range 2000-200 MHz. Therefore, it looks like not only the DPS but also the high-frequency drifting continua and other slowly drifting structures can be connected with the plasmoid ejection.…”

The relativistic solar particle event of 2005 January 20: origin of delayed particle acceleration

“…In the 2000 Jul. 14 event (W 07 • ; Klein et al 2001a) the GLE was accompanied by a Type IV burst with a spectrum that drifted slowly towards lower frequencies (see the radio spectrum in Klein et al 2001b). Both the radio spectrum and the relativistic proton timing were similar to Episode 5 of the 2005 Jan. 20 event.…”

Temporal Evolution of Solar Energetic Particle Spectra

“…The X5.7 flare started at 10:03 on the 14th of July (Bastille Day) at N22W07, while the CME started at 10:54 as a halo event with a velocity of 1674 km/sec at N20W08. Together, these events were widely observed at ground level on multiple Earth based neutron monitors, and with particle and magnetic field measurements being made directly with the WIND, ACE, and SOHO spacecraft, as reported by Belov et al (2001), Klein et al (2001), and Bieber et al (2002). Important observations were also reported from the ULYSSES data by Zhang et al (2003), at which time the spacecraft was at a distance of 3.17 AU from the Sun, and at 62…”