Turbulence plays a critical role in controlling the physics of the collisionless, magnetized plasmas that pervade our solar system as well as astrophysical systems throughout the cosmos. The pristine solar wind near Earth offers a natural laboratory for the in situ observation of turbulent fields and particle distributions that are represenative of those througout the universe. Understanding the transport of mass, momentum, and energy, and associated dissipation in such systems is important and compelling, but its exact nature remains a mystery owing primarily to our past, present, and planned future approaches to reveal it.
To date, all in situ observations of solar wind plasmas and magnetic fields have been single point measurements (i.e., ACE, WIND), or have focused on a single scale through the use of carefully controlled clusters of four spacecraft (i.e., Cluster, MMS). Turbulence is fundamentally a multi-scale, three-dimensional, time-evolving phenomenon and therefore niether single point measurements nor even a cluster of four spacecraft provide insight into the full nature of the turbulent medium.
To reveal the full temporal and spatial structure of turbulence requires observations at an array of points that far exceeds the tetrahedral configurations flown to date. With the advent of low resource sensors and small satellites, such arrays of spacecraft are now possible and promise to transform our knowledge of turbulence. Rather than flying in formation, a swarm of small spacecraft will enable direct measurement of a wide range of spatial and temporal scales that span physical ranges of interest.
This website describes a newly-feasible, innovative mission concept employing such a swarm of many small spacecraft. The cost-effective HelioSwarm mission will reveal and quantify key unknown aspects of turbulence, allowing us to understand the cascade of energy from longer scale and time sizes toward and into smaller scales and shorter times.
The HelioSwarm mission team welcomes your feedback. Please consider leaving your comments at our HelioSwarm blog at: https://helioswarm.wordpress.com