DOI: 10.5281/zenodo.14948004
title: Wind Satellite Data for Ubiquitous Occurrences of Multi-scale Layers of Magnetic Reconnection across a Solar Wind Stream Interaction Region at 1 AU

description: The dataset provided herein contains 71 magnetic reconnection exhausts as recorded by the Wind spacecraft during an 8-day period from 2019-01-01/00:00 UT to 2019-01-09/00:00 UT. The interval is centered at a single stream interaction region (SIR) from 2019-01-04/10:11:20 UT to 2019-01-05/09:58:00 UT. The SIR formed as a fast wind stream caught up with a slow wind ahead. In the process a region of plasma and field compression formed between a pair of forward and reverse shocks with a presence of several large-scale current sheet crossings of an embedded heliospheric current sheet and adjacent magnetic field inversions deep inside the SIR.

Detailed information for the 71 exhausts is available in the ASCII text file [wind_lmn_manual_cs_walen_sb_zenodo.txt]. This information includes start and stop dates and times of the underlying (active) current sheets, their associated LMN unit vectors (base: GSE), times to reproduce Walén predictions as well as average values of associated parameters (B, V, Np, Tp) adjacent to each active current sheet (CS). The file also contains the maximum and minimum of several parameters within each exhaust period.

The underlying Wind spacecraft measurements are available from NASA CDAWeb [https://cdaweb.gsfc.nasa.gov/]. The list of 71 events were obtained from an automated survey based on a sliding window technique of 42 different sizes. There are 40 windows at 30 s cadence from dt=30 s to dt=20 min and two windows at 16 s and 44 s.

 

There are two exhaust-overview PDF files with 71 pages each for the 71 magnetic reconnection exhausts.

wind_20190101_20190109_exhaust_opt2_yes_select_sorted_71FINAL_H2MFI.PDF:

This PDF file contains 71 exhaust event figures with 6 panels showing (from top to bottom) plasma density (Np), proton average temperature (Tp), BL, VL, BM, BN. The individual hybrid-LMN system is given below each plot as Lc, Mc, Nc unit vectors (base: GSE) for each current sheet. Note that this system is based on a cross-product normal (Nc) to the CS. There are three vertical lines. A solid green line corresponds to an optimum, change-over time (topt) between two Walen predictions from the left (leading side) and right (trailing side) of the CS. The CS start and stop times (CS1 and CS2) are shown as dotted vertical lines. Here, a Walen prediction of the measured VL component of the ion velocity from the WIND 3DP instrument is colored red from both sides of the CS.

wind_20190101_20190109_exhaust_opt2_yes_select_sorted_71FINAL_H2MFI_cptimes.PDF:

This PDF file contains 71 exhaust event pages with 11 panels: P, Np, Tp, V, B, BL, VL, BM, VM, BN, VN. Here, Pt=Pb+Pp is the sum of the magnetic field pressure (Pb: red) and the proton plasma pressure (Pp: blue). Any deviation from total pressure balance across CSs can most likely be traced to the electron pressure (Pe). Each page also includes Lc, Mc, Nc unit vectors in GSE below the plots. The two red solid lines correspond to CS1 (start) and CS2 (end) times of the exhaust-associated CS. A pair of dotted lines (black and red) before CS1 mark the leading period used to obtain an average magnetic field Bgse1 = [Bx1, By1, Bz1]. A pair of dotted lines (red and black) after CS2 mark the trailing period used to obtain an average Bgse2 = [Bx2, By2, Bz2]. The two magnetic field vectors are used to obtain the Nc = Bgse1 x Bgse2 / |Bgse1 x Bgse2| cross-product normal determination. Here, a Walen prediction of the measured VL component of the ion velocity from the WIND 3DP instrument is colored in red from the leading (first) side and it is colored in green from the trailing (second) side of the CS. The change-over time (topt) is where the sense of BL and VL changes between being correlated and anti-correlated.

 

Figure1_Vy_165.PDF:

This PDF file contains three pages of the same Wind satellite data but shown for three separate time periods: 8 days from 2019-01-01/00:00 UT to 2019-01-09/00:00 UT (page 1), 2 days from 2019-01-04/00:00 UT to 2019-01-06/00:00 UT (page 2), and 1.5 days from 2019-01-04/06:00 UT to 2019-01-05/18:00 UT (page 3). The panels show: (a) pitch-angle distribution of 165 eV electron differential energy flux, (b) ratio of parallel to antiparallel 165 eV electron energy flux, (c) magnetic field strength (B), (d) Bxgse component of the magnetic field vector, (e) 360o azimuthal phi-angle of the ecliptic-plane magnetic field (Bxgse and Bygse) with phi=0o and phi=360o corresponding to Bxgse>0 and Bygse=0, and phi=90o for Bxgse=0 and Bygse>0, (f) solar wind speed (V), (g) Vygse component of the solar wind velocity, (h) proton number density (Np), (i) proton average temperature (Tp). The two red, horizontal dotted lines in panel (e) mark phi=45o and phi=225o with a heliospheric magnetic field (HMF) at 45o < phi < 225o corresponding to an away-directed HMF. There are three magenta-colored, vertical dotted lines marking a forward shock at 2019-01-04/10:11:20 UT, a stream interface at 2019-01-04/21:48:00 UT, and a reverse shock at 2019-01-05/09:58:00 UT. The two blue, vertical dotted lines at 2019-01-04/16:56:40 UT and 2019-01-05/02:20:30 UT mark a magnetic sector boundary between an open Bgse directed away from the Sun and an open Bgse directed toward the Sun. These times are obtained from strahl polarity changes of 165 eV strahl energy flux information from the eESA 3DP instrument.

 

There are four Figure 2 files:

Figure2_Bx_165ratio.PDF, Figure2_By_165ratio.PDF, Figure2_Bz_165ratio.PDF, and Figure2_SB_165_427eV.

Each of the three Figure2_B*_165ratio.PDFs contains 8 pages for different time periods with each new page zooming in from an 8-day period (page 1) toward a central magnetic sector period from 2019-01-04/16:56:40 UT to 2019-01-05/02:20:30 UT. Page 8 shows the 11-hour period from 2019-01-04/16:00 UT to 2019-01-05/03:00 UT. The three PDFs only differ in terms of panel (b) that either shows the Bxgse, Bygse or Bzgse component of a 3-s cadence magnetic field. From top to bottom: (a) B magnitude, (b) GSE component of Bgse (x, y or z), (c) azimuthal phi-angle of Bgse from Bxgse and Bygse, (d) solar wind speed, (e) Np, (f) Tp, (g) ratio of parallel to antiparallel 165 eV strahl energy flux, (h) total number of obtained reconnection exhaust events in subsequent six-hour periods with time stamps at the center of each period (03:00 UT for 00:00-06:00 UT interval, e.t.c.) and using the Walen topt time inside each exhaust interval. The vertical-colored lines mark topt times for all 71 exhausts. Colors represent the dcs=<VN>*∆tcs normal width of each active current sheet: 17 exhausts at dcs<50 di (light blue), 16 exhausts at 50≤dcs<100 di (green), 24 exhausts for 100≤dcs<500 di (yellow), 14 exhausts at dcs≥500 di (red). Here, ∆tcs is actual CS duration (seconds) and <VN>=(VN1+VN2)/2 with VN1 the average normal speed before the CS and VN2 after the CS in km/s. Widths are normalized to the average ion inertial length di=c/ωpi next to the CS with c being the speed of light and ωpi the proton plasma frequency (see wind_lmn_manual_cs_walen_sb_zenodo.txt file for ∆tcs, VN1, VN2, di data).

 

Figure2_SB_165_427eV.PDF:

This PDF file contains three pages of the same Wind satellite data for the same 11-hour period from 2019-01-04/16:00 UT to 2019-01-05/03:00 UT close to the sector boundary except that panel (e) displays the Bxgse (page 1), Bygse (page 2) or Bzgse (page 3) component of the magnetic field. Black vertical lines display all exhaust topt times in this 11-hour period. The panels show: (a) pitch-angle distribution of 165 eV electron energy flux, (b) pitch-angle distribution of 427 eV electron energy flux, (c) ratio of parallel to antiparallel energy flux for 165 eV strahl (black) and 427 eV strahl (red), (d) magnetic field strength (B), (e) GSE component of Bgse (x, y or z), (f) 360o azimuthal phi-angle of the ecliptic-plane magnetic field (Bxgse and Bygse), (g) solar wind speed, (h) proton number density, (i) proton average temperature.

 

For further details of this solar wind study, we refer to a manuscript entitled "Ubiquitous Occurrences of Multi-scale Layers of Magnetic Reconnection across a Solar Wind Stream Interaction Region at 1 AU" by S. Eriksson et al.