Cavitons and spontaneous hot flow anomalies in a hybrid-Vlasov global magnetospheric simulation

Abstract. In this paper we present the first identification of foreshock cavitons and the formation of spontaneous hot flow anomalies (SHFAs) with the Vlasiator global magnetospheric hybrid-Vlasov simulation code. In agreement with previous studies we show that cavitons evolve into SHFAs. In the presented run, this occurs very near the bow shock. We report on SHFAs surviving the shock crossing into the downstream region and show that the interaction of SHFAs with the bow shock can lead to the formation of a magnetosheath cavity, previously identified in observations and simulations. We report on the first identification of long-term local weakening and erosion of the bow shock, associated with a region of increased foreshock SHFA and caviton formation, and repeated shock crossings by them. We show that SHFAs are linked to an increase in suprathermal particle pitch-angle spreads. The realistic length scales in our simulation allow us to present a statistical study of global caviton and SHFA size distributions, and their comparable size distributions support the theory that SHFAs are formed from cavitons. Virtual spacecraft observations are shown to be in good agreement with observational studies.

[1]  X. Blanco‐Cano,et al.  Magnetosheath jet properties and evolution as determined by a global hybrid-Vlasov simulation , 2018, Annales Geophysicae.

[2]  S. Hoilijoki,et al.  On the Importance of Spatial and Velocity Resolution in the Hybrid-Vlasov Modeling of Collisionless Shocks , 2018, Front. Phys..

[3]  X. Blanco‐Cano,et al.  Cavitons and spontaneous hot flow anomalies in a hybrid-Vlasov global simulation , 2018 .

[4]  B. Jakosky,et al.  Spontaneous hot flow anomalies at Mars and Venus , 2017 .

[5]  G. Collinson,et al.  Structure and Properties of the Foreshock at Venus , 2017 .

[6]  N. Omidi,et al.  Traveling Foreshocks and Transient Foreshock Phenomena , 2017, 1711.01321.

[7]  Can Huang,et al.  Reformation of rippled quasi‐parallel shocks: 2‐D hybrid simulations , 2017 .

[8]  Y. Pfau‐Kempf.  Vlasiator From local to global magnetospheric hybrid-Vlasov simulations , 2016 .

[9]  O. Hannuksela,et al.  Mirror modes in the Earth's magnetosheath: Results from a global hybrid‐Vlasov simulation , 2016 .

[10]  H. Zhang,et al.  Impacts of spontaneous hot flow anomalies on the magnetosheath and magnetopause , 2016 .

[11]  B. Lembège,et al.  Formation of downstream high‐speed jets by a rippled nonstationary quasi‐parallel shock: 2‐D hybrid simulations , 2016 .

[12]  L. Wilson.  Low Frequency Waves at and Upstream of Collisionless Shocks , 2016 .

[13]  L. L. Zhao,et al.  Case and statistical studies on the evolution of hot flow anomalies , 2015 .

[14]  O. Hannuksela,et al.  Ion distributions in the Earth's foreshock: Hybrid‐Vlasov simulation and THEMIS observations , 2015 .

[15]  M. Fujimoto,et al.  What Controls the Structure and Dynamics of Earth’s Magnetosphere? , 2015 .

[16]  O. Hannuksela,et al.  ULF foreshock under radial IMF: THEMIS observations and global kinetic simulation Vlasiator results compared , 2015 .

[17]  T. Horbury,et al.  Global impacts of a Foreshock Bubble: Magnetosheath, magnetopause and ground-based observations , 2014, 1409.0390.

[18]  Minna Palmroth,et al.  Vlasiator: First global hybrid-Vlasov simulations of Earth's foreshock and magnetosheath , 2014 .

[19]  H. Zhang,et al.  Parametric dependencies of spontaneous hot flow anomalies , 2014 .

[20]  Stefano Markidis,et al.  Two-way coupling of a global Hall magnetohydrodynamics model with a local implicit particle-in-cell model , 2014, J. Comput. Phys..

[21]  D. Sibeck,et al.  Magnetosheath filamentary structures formed by ion acceleration at the quasi‐parallel bow shock , 2014 .

[22]  C. Russell,et al.  Statistical study of foreshock cavitons , 2013 .

[23]  T. Horbury,et al.  Magnetospheric response to magnetosheath pressure pulses: A low‐pass filter effect , 2013 .

[24]  H. Zhang,et al.  Spontaneous hot flow anomalies at quasi‐parallel shocks: 1. Observations , 2013 .

[25]  D. Burgess,et al.  Microphysics of Quasi-parallel Shocks in Collisionless Plasmas , 2013 .

[26]  X. Blanco‐Cano,et al.  Dynamics of the foreshock compressional boundary and its connection to foreshock cavities , 2013 .

[27]  H. Zhang,et al.  Spontaneous hot flow anomalies at quasi‐parallel shocks: 2. Hybrid simulations , 2013 .

[28]  A. Spitkovsky,et al.  COSMIC-RAY-INDUCED FILAMENTATION INSTABILITY IN COLLISIONLESS SHOCKS , 2012, 1211.6765.

[29]  C. Russell,et al.  Foreshock cavitons for different interplanetary magnetic field geometries: Simulations and observations , 2011 .

[30]  C. Russell,et al.  Multi-spacecraft study of foreshock cavitons upstream of the quasi-parallel bow shock , 2011 .

[31]  Hank Childs,et al.  VisIt: An End-User Tool for Visualizing and Analyzing Very Large Data , 2011 .

[32]  C. Russell,et al.  Analysis of waves surrounding foreshock cavitons , 2010 .

[33]  Uppsala,et al.  Supermagnetosonic jets behind a collisionless quasiparallel shock. , 2009, Physical review letters.

[34]  I. Dandouras,et al.  Magnetosheath cavities: case studies using Cluster observations , 2009 .

[35]  Z. Németh,et al.  A global study of hot flow anomalies using Cluster multi-spacecraft measurements , 2009, 1807.07368.

[36]  C. Russell,et al.  Global hybrid simulations: Foreshock waves and cavitons under radial interplanetary magnetic field geometry , 2009 .

[37]  N. Omidi.  Formation of cavities in the foreshock , 2007 .

[38]  D. Sibeck,et al.  Formation of hot flow anomalies and solitary shocks , 2007 .

[39]  C. Russell,et al.  Macrostructure of collisionless bow shocks: 2. ULF waves in the foreshock and magnetosheath , 2006 .

[40]  C. Russell,et al.  Macrostructure of collisionless bow shocks: 1. Scale lengths , 2005 .

[41]  J. Eastwood,et al.  Quasi‐monochromatic ULF foreshock waves as observed by the four‐spacecraft Cluster mission: 1. Statistical properties , 2005 .

[42]  A. Balogh,et al.  Quasi-parallel Shock Structure and Processes , 2005 .

[43]  A. Balogh,et al.  Quasi-perpendicular Shock Structure and Processes , 2005 .

[44]  J. Sauvaud,et al.  Production of gyrating ions from nonlinear wave-particle interaction upstream from the Earth's bow shock: A case study from Cluster-CIS , 2003 .

[45]  G. Parks,et al.  Three‐dimensional observations of gyrating ion distributions far upstream from the Earth's bow shock and their association with low‐frequency waves , 2001 .

[46]  David G. Sibeck,et al.  Comprehensive study of the magnetospheric response to a hot flow anomaly , 1999 .

[47]  S. Schwartz.  Hot flow anomalies near the Earth's bow shock , 1995 .

[48]  R. Schunk,et al.  Field-aligned expansion of plasma clouds in the ionosphere , 1995 .

[49]  M. Fujimoto,et al.  Two‐dimensional simulations of supercritical quasi‐parallel shocks: Upstream waves, downstream waves, and shock re‐formation , 1993 .

[50]  Steven J. Schwartz,et al.  Quasi-parallel shocks: A patchwork of three-dimensional structures , 1991 .

[51]  D. Burgess.  Cyclic behavior at quasi‐parallel collisionless shocks , 1989 .

[52]  M. Kivelson,et al.  Observations of the earth's bow shock under high Mach number/high plasma beta solar wind conditions , 1988 .

[53]  S. Schwartz,et al.  An active current sheet in the solar wind , 1985, Nature.

[54]  C. Russell,et al.  Upstream hydromagnetic waves and their association with backstreaming ion populations: ISEE 1 and 2 observations , 1981 .