A decade of questions about magnetic reconnection

摘要

Students attending the Center for Integrated Space Weather Modeling (CISM) summer school [Simpson, 2004; Gross et al., 2009] not only ask questions of the lecturers but also submit written questions at the end of each lecture sessions. Over the last decade we have collected approximately 3000 of these submitted questions about space weather and associated physical processes. This article addresses questions commonly asked about magnetic reconnection. Some of the questions are about points that are unclear, while others illuminate how students process new or reprocess previous information and sometimes form common misconceptions about reconnection. Some of these issues arise when students apply conceptual plasma approximations (e.g., “frozen-in-flux” or “particles trapped on field lines”) and apply them inappropriately. Another source of student misconceptions is the use of the term reconnection by researchers to describe both the process that reconnects the magnetic field at the reconnection point and also the results of field reconfiguration—accelerated and heated plasmas, high-energy particles, and X-rays emissions. Students may also interpret the standard schematic drawing of X-point reconnection literally, believing that reconnection is confined to a plane, and they often misinterpret the relevant length scales. In addition, student questions indicate that they treat field lines, rather than the fields themselves, as physical objects. The questions below are composite questions gleaned from review of the actual questions that students asked during more than a decade of summer schools. Along with identifying the questions, the aim of this article is to document the responses and provide a few useful references for instructors and students. Rather than a scholarly review of the subject, this manuscript provides succinct answers to common questions about magnetic reconnection.