A double-cusp type electrostatic analyzer for high-cadence solar-wind suprathermal ion observations.

Area of Science:

• Space Physics
• Plasma Physics
• Instrument Development

Background:

• Existing ion instruments are large and heavy for suprathermal energy measurements.
• Low-flux suprathermal ion observations require long integration times, limiting data characterization.

Purpose of the Study:

• Introduce a novel electrostatic analyzer concept, the Double-Cusp Analyzer for SupraThermals (DCAST).
• Develop a compact instrument for high-cadence, high-resolution suprathermal ion measurements.
• Address limitations of current instruments in terms of size, mass, and data acquisition speed.

Main Methods:

• Designed and prototyped the Double-Cusp Analyzer for SupraThermals (DCAST) with a double-shell cusp structure.
• Conducted laboratory measurements to verify performance (geometric factor, K-factor, energy resolution).
• Investigated noise sources, including cross-sector contamination and extreme ultraviolet photons, and analyzed the impact of the inner and outer sector voltage ratio (R).

Main Results:

• DCAST effectively covers the suprathermal energy range (2-300 keV/q), including heated solar wind and pickup ions.
• The prototype demonstrated high cadence, high angular resolution, and wide angle coverage.
• Laboratory tests validated the instrument's performance and identified key operational parameters.

Conclusions:

• DCAST presents a viable solution for efficient suprathermal ion measurements in space plasmas.
• The novel design conserves mass and size while enhancing data quality and acquisition speed.
• Further investigation into the double-shell design parameters can optimize electrostatic analyzer performance.