Kinetic Simulation of Segmented Plasma Flow Meter Response in the Ionospheric Plasma

• Published in: Journal of geophysical research. Space physics Vol. 126; no. 5
• Main Authors: Liu, G., Marchand, R.
• Format: Journal Article
• Language: English
• Published: 01.05.2021
• Subjects: PIC simulation; plasma flow meter; segmented flow meter; space plasma
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1029/2021JA029120

A relatively simple design of a segmented flow meter is presented for measuring in situ plasma flow velocities and other space plasma parameters. The response of the flow meter to space environment is simulated for plasma conditions representative of the ionosphere at mid and low latitudes using a Particle in cell code. A synthetic data set consisting of ion currents collected by several segments of the flow meter, and the physical parameters for which they were calculated, is then used to construct a solution library from which inference models can be constructed, using radial basis function and neural network regressions. Simulation results show that with such a flow meter, it should be possible to infer plasma flow velocities in the direction perpendicular to the ram direction, with uncertainties of ±45 m/s or less. Models can also be constructed to infer plasma densities, with a maximum relative error of 23%. This work is presented as a first assessment and proof of concept for an original design of a simple and robust flow meter. Plain Language Summary We present a new plasma flow meter geometry intended to measure plasma flow velocities in Earth ionosphere. Kinetic simulations are used to construct a synthetic data set from which inference models are constructed and validated. This new concept of flow meter is simple and robust, and the analysis shows that transverse velocities can be estimated with a root mean square error of 20 m/s, in the range of plasma environment conditions considered. It is also shown that the same instrument can be used to infer the electron densities with a root mean square relative error of order 10%. Key Points Currents collected by fixed‐biased segments in a flow meter are calculated using kinetic simulations Regression models are constructed and validated, for ionospheric plasma densities and flow velocities, using synthetic data The magnitude and distribution of collected currents on segments are used to determine transverse plasma flow velocities and densities