Characteristic size and shape of the mirror mode structures in the solar wind at 0.72 AU

Abstract

[1] We investigate the structure of mirror modes in the solar wind at 0.72 AU using Venus Express magnetic field measurements. The mirror mode structure is identified as the presence of magnetic depression or magnetic ''holes'' in the solar wind with little or no directional change across them. We determine the characteristic size and shape of these structures by examining their durations as a function of the orientation of the magnetic field to the solar wind flow. The mirror mode structure is best fitted with an ellipsoid of revolution, and the resultant shape of the mirror mode structure is a prolate spheroid, or in other words, a rotational ellipsoid. We introduce two parameters, namely the width across the field and the eccentricity to give a full description of the size and shape of the structures. We find that the mirror mode structures in the solar wind are twodimensional and are more elongated along the magnetic field direction. Citation: Zhang, T. L., et al. (2008), Characteristic size and shape of the mirror mode structures in the solar wind at 0.72 AU, Geophys. Res. Lett., 35, L10106,

Mirror‐mode storms inside stream interaction regions and in the ambient solar wind: A kinetic study

“…In this case, the storms were observed in the leading edge of a SIR detected on 10 July 2007 at 09:45. When observed in great detail (see subsequent figures), MMSs resemble mirror-mode trains reported in previous works of mirror modes in the solar wind (see for instance, Zhang et al [2008], and references therein). However, there are certain features that, to the naked eye, make them different from ordinary trains.…”

“…[8] For the solar wind, magnetic holes have also been observed at various heliocentric distances either as isolated holes or trains of closely-spaced magnetic holes [Winterhalter et al, 1994;Zhang et al, 2008;Russell et al, 2008]. Recently, using STEREO high-resolution magnetic field data, Russell et al [2009] reported several mirror-mode events of small amplitude trains, which included not only holes, but also peaks that persisted for hours and were referred to as "mirror-mode storms".…”

Statistical analysis of mirror mode waves in sheath regions driven by interplanetary coronal mass ejection

“…However, MMs have typically larger amplitudes behind quasi-parallel shocks (Génot et al, 2009b). In addition, while also isolated MMs exist (Winterhalter et al, 1994;Zhang et al, 2008), most MMs in planetary magnetosheaths occur as sequences of peaks or dips, so called MM trains (Tsurutani et al, 2011b).…”

“…To identify individual MMs, we investigate the minima and maxima in the magnetic field data of the combined intervals that have passed the MVA test by applying methods used by Zhang et al (2008Zhang et al ( , 2009 (B i −B) 3 , and the variance σ = δ 2 . Skewness describes the asymmetry of a distribution and is positive for intervals with peaks and negative for intervals with dips (see e.g., Osmane et al, 2015).…”

“…They are frequently observed in heliospheric plasma, in particular in different sheath structures. They are the most widely studied in the planetary magnetosheaths (e.g., Tsurutani et al, 1982;Hellinger et al, 2003;Soucek et al, 2008Soucek et al, , 2015Volwerk et al, 2008;Génot et al, 2009b;Herčík et al, 2013;Schmid et al, 2014;Volwerk et al, 2016), but also found in cometosheaths (e.g., Russell et al, 1991;Glassmeier et al, 1993;Tsurutani et al, 1999;Schmid et al, 2014), in the heliosheath (e.g., Liu et al, 2007;Génot, 2008;Tsurutani et al, 2011a) and ahead of the dipolarization front (Wang et al, 2016). MMs are also studied in the solar wind (e.g., Hellinger et al, 2006Hellinger et al, , 2017Bale et al, 2009;Russell et al, 2009), behind interplanetary shocks ) and in addition in interplanetary coronal mass ejections (ICMEs; Siu-Tapia et al, 2015).…”