TY - JOUR
T1 - Mercury's cross-tail current sheet
T2 - Structure, X-line location and stress balance
AU - Poh, Gangkai
AU - Slavin, James A.
AU - Jia, Xianzhe
AU - Raines, Jim M.
AU - Imber, Suzanne M.
AU - Sun, Wei Jie
AU - Gershman, Daniel J.
AU - DiBraccio, Gina A.
AU - Genestreti, Kevin J.
AU - Smith, Andy W.
N1 - Funding Information:
All data analyzed in this paper are archived with the NASA Planetary Data System. Support was provided by NASA Discovery Data Analysis Program grants NNX15K88G and NNX15AL01G, Heliophysics Supporting Research NNX15AJ68G, Living With a Star NNX16AJ67G, and Solar System Workings Program grant NNX15AH28G to the University of Michigan. D.J.G. and G.A.D. were supported by NASA ROSES grant NNX16AJ05G. G.A.D. was supported by a NASA Postdoctoral Program appointment at the NASA Goddard Space Flight Center, administered by Universities Space Research Association through a contract with NASA. S.M.I. acknowledges the support of the Leverhulme Trust.
PY - 2017/2/20
Y1 - 2017/2/20
N2 - The structure, X-line location, and magnetohydrodynamic (MHD) stress balance of Mercury's magnetotail were examined between −2.6 < XMSM < −1.4 RM using MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) measurements from 319 central plasma sheet (CPS) crossings. The mean plasma β in the CPS calculated from MESSENGER data is ~ 6. The CPS magnetic field was southward (i.e., tailward of X-line) ~ 2–18% of the time. Extrapolation of downtail variations in BZ indicates an average X-line location at −3 RM. Modeling of magnetic field measurements produced a cross-tail current sheet (CS) thickness, current density, and inner CS edge location of 0.39 RM, 92 nA/m2 and −1.22 RM, respectively. Application of MHD stress balance suggests that heavy planetary ions may be important in maintaining stress balance within Mercury's CPS. Qualitative similarities between Mercury's and Earth's magnetotail are remarkable given the differences in upstream conditions, internal plasma composition, finite gyro-radius scaling, and Mercury's lack of ionosphere.
AB - The structure, X-line location, and magnetohydrodynamic (MHD) stress balance of Mercury's magnetotail were examined between −2.6 < XMSM < −1.4 RM using MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) measurements from 319 central plasma sheet (CPS) crossings. The mean plasma β in the CPS calculated from MESSENGER data is ~ 6. The CPS magnetic field was southward (i.e., tailward of X-line) ~ 2–18% of the time. Extrapolation of downtail variations in BZ indicates an average X-line location at −3 RM. Modeling of magnetic field measurements produced a cross-tail current sheet (CS) thickness, current density, and inner CS edge location of 0.39 RM, 92 nA/m2 and −1.22 RM, respectively. Application of MHD stress balance suggests that heavy planetary ions may be important in maintaining stress balance within Mercury's CPS. Qualitative similarities between Mercury's and Earth's magnetotail are remarkable given the differences in upstream conditions, internal plasma composition, finite gyro-radius scaling, and Mercury's lack of ionosphere.
KW - cross-tail current sheet
KW - magnetotail structure
KW - Mercury
KW - Near-Mercury Neutral Line
KW - stress balance
UR - http://www.scopus.com/inward/record.url?scp=85011394772&partnerID=8YFLogxK
U2 - 10.1002/2016GL071612
DO - 10.1002/2016GL071612
M3 - Article
AN - SCOPUS:85011394772
SN - 0094-8276
VL - 44
SP - 678
EP - 686
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 2
ER -