Letter to the Editor

Chromospheric polarity reversal on sunspots: New insight from spectro-polarimetric measurements

¹ THEMIS, C/O IAC, via Lactea, 38200 La Laguna, Tenerife, Spain
² LESIA, Observatoire de Meudon, 92195 Meudon Cedex principal, France
³ Dipartimento di Fisica – Ponte P. Bucci, Cubo 31C, Universitá della Calabria, 87036 Rende (CS), Italy

Corresponding author: C. Briand, cbriand@themis.iac.es

Received: 12 March 2003
Accepted: 13 April 2003

Abstract

We present here spectro-polarimetric observations of chromospheric and photospheric lines on an active region. We show that the presence of polarity reversal between photosphere and chromosphere cannot be detected relying on magnetograms and broad band and even narrow band filters only. We demonstrate that opposite signs in CaII magnetograms in sunspots compare to photospheric magnetograms are not due to a reversal of the magnetic field, but rather due to the presence of line core emission as suggested from theoretical arguments by Sánchez Almeida ([CITE]).