Hα Moreton waves observed on December 06, 2006

A 2D case study

¹ Observatorio Astronómico Félix Aguilar, Universidad Nacional de San Juan, Argentina
e-mail: cfrancile@unsj-cuim.edu.ar
² Instituto de Astronomía Teórica y Experimental, Córdoba, Laprida 854, X5000 BGR, Córdoba, Argentina
³ Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Argentina
⁴ Consejo Nacional de Investigaciones Científicas y Técnicas, Av. Rivadavia 1917 C1033AAJ Ciudad Autónoma de Buenos Aires, Argentina
⁵ Instituto de Astronomía y Física del Espacio, Casilla de Correo 67-Sucursal 28, C14282AA Ciudad Autnóma de Buenos Aires, Argentina

Received: 1 September 2011
Accepted: 22 January 2013

Abstract

Context. We present high temporal resolution observations of a Moreton wave event detected with the Hα Solar Telescope for Argentina (HASTA) in the Hα line 656.3 nm, on December 6, 2006.

Aims. The aim is to contribute to the discussion about the nature and triggering mechanisms of Moreton wave events.

Methods. We describe the HASTA telescope capabilities and the observational techniques. We carried out a detailed analysis to determine the flare onset, the radiant point location, the kinematics of the disturbance and the activation time of two distant filaments. We used a 2D reconstruction of the HASTA and corresponding TRACE observations, together with conventional techniques, to analyze the probable origin of the phenomenon.

Results. The kinematic parameters and the probable onset time of the Moreton wave event are determined. A small-scale ejectum and the winking of two remote filaments are analyzed to discuss their relation with the Moreton disturbance.

Conclusions. The analysis of the Moreton wave event favors the hypothesis that the phenomenon can be described as the chromospheric imprint of a single fast coronal shock triggered from a single source in association with a coronal mass ejection. Its onset time is concurrent with a Lorentz force peak measured in the photosphere, as stated by other authors. However, the existence of multiple shock waves that were generated almost simultaneously cannot be discarded.