Solar Wind Ion Analyzer (SWIA)

The SWIA instrument measures the solar wind and ion density and velocity in the magnetosheath of Mars. (Courtesy UCB/SSL)

The Solar Wind Ion Analyzer (SWIA) is a part of the Particles and Fields (P & F) Package and measures the solar wind and magnetosheath proton flow around Mars and constrains the nature of solar wind interactions with the upper atmosphere.

Goals:

Determine the ionization rates of neutrals from charge exchange, as an input to atmospheric loss processes
Determine the pickup acceleration of newly formed ions by the v x B electric field
Measure the flow of solar wind energy through the Martian magnetosphere
Measure the structure and variability of the Martian magnetosphere
Measure basic space plasma phenomena, including reconnection, flux ropes, plasmoids, bulk plasma escape, auroral processes, and boundary instabilities, throughout the Martian system

Observations:

Measure the properties of solar wind and magnetosheath ions, including density, temperature, and velocity, in order to determine the energy input to the upper atmosphere, the charge exchange rate, and the bulk plasma flow from solar wind speeds (~350 to ~1000 km/s) down to stagnating magnetosheath speeds (tens of km/s)

Shown here is a cross-cut view of the MAVEN Solar Wind Ion Analyzer optics, which enables the instrument to measure density and velocity distributions of solar wind and magnetosheath protons at Mars. (Courtesy Jasper Halekas, UCB/SSL)

Technical details and heritage:

Coarse 3d covers 360°x90° with 22.5° resolution and energies 5 eV/q – 25 keV/q
Fine 3d covers solar wind beam w/ 4.5° resolution and 10% energy windows
Intrinsic time resolution of 4 s
Mechanical attenuator provides variable dynamic range to cover from tenuous magnetosphere up to extreme solar wind fluxes [5×10⁴ to 7×10¹¹ eV/(cm² s sr eV)]
Heritage from Wind, FAST, and THEMIS

Instrument publications:

Structure, dynamics, and seasonal variability of the Mars-solar wind interaction: MAVEN Solar Wind Ion Analyzer in-flight performance and science results
(Journal of Geophysical Research—Space Physics article—published online January 2017)—Download PDF (12 MB)

The Solar Wind Ion Analyzer for MAVEN (Space Science Reviews article—published online November 2013)—Download PDF (2 MB)

Jasper Halekas - MAVEN SWIA instrument lead — Jasper Halekas—SWIA Instrument Lead

The SWIA instrument lead is Jasper Halekas (University of Iowa). For more about Halekas, visit: http://www.physics.uiowa.edu/~jhalekas.

MAVEN Science Community Workshop Presentation
(Dec. 2, 2012)