ENA particles enter the instrument through the ring shaped collimatorA device at the entrance to a sensor instrument that narrows a beam of particles or waves, such as light or energetic neutral atoms, into a more parallel or aligned stream. This helps improve the precision and accuracy of measurements or imaging by reducing the spread of the beam; the “gateway” into a sensor. encircling a signal processing unit in the sensor head. The collimator defines the range of directions from which incoming particles can enter the instrument at any given moment, channeling them toward a ring of ultra thin carbon foils that convert the neutral ENA particles into positively charged ions.

An electrified deflector shield surrounds the entire sensor head preventing charged solar windA stream of charged particles, mostly protons and electrons, that escapes into the Sun's outer atmosphere at high speeds and streams out into the solar system in all directions. particles from entering the collimator.

Once the ENAsEnergetic Neutral Atoms are atoms with no charge that move very quickly. These atoms have equal numbers of positively-charged protons and negatively-charged electrons. ENAs form when charged particles from the solar wind travel outward and encounter atoms from the interstellar medium. Because the ENAs are neutral, they do not react to any magnetic fields. Some of these ENAs travel toward the inner solar system and are captured by the IMAP spacecraft. have been ionized, they enter an electrostatic energy analyzer or ESAAn Electrostatic Analyzer is an instrument used in ion optics that employs an electric field to allow the passage of only those ions or electrons that have a given specific energy. It usually also focuses these particles (concentrates them) into a smaller area..

This part of the instrument consists of two electrically charged plates that guide ions within a specific energy range through the analyzer's U-shaped gap and into the timeA measure of the flow of events. of flight or TOF detectorAn instrument which is used to discover that something is present somewhere, or to measure how much of something there is. system. The ESA is stepped through a set of 9 voltage settings to select ions within 9 different energy ranges.

The TOF detector uses the time it takes for a particle to travel between a pair of ultra thin carbon foils to determine the particle's velocity.

The combination of velocity from the TOF measurement and energy from the ESA allows the signal processing unit to distinguish between true heliosphereThe bubble-like region surrounding the solar system inflated by the solar wind, shielding the solar system from interstellar radiation. ENAs and unwanted background particles. The part of the sky that the ENA arrived from is determined by the direction that the instrument was pointing at the instant the ENA entered the collimator.

Learn more about imap-hi

Using the energy levels of the converted ENAsEnergetic Neutral Atoms are atoms with no charge that move very quickly. These atoms have equal numbers of positively-charged protons and negatively-charged electrons. ENAs form when charged particles from the solar wind travel outward and encounter atoms from the interstellar medium. Because the ENAs are neutral, they do not react to any magnetic fields. Some of these ENAs travel toward the inner solar system and are captured by the IMAP spacecraft. and the direction they entered IMAP-HiThe IMAP-Hi instrument consists of an identical pair of imagers that collect, count, measure, and map energetic neutral atoms (ENAs) of energies from 0.4 to 15.6 kiloelectron volts (keV) from two different angles. Together they will be able to image the global sky.’s collimators, scientists can create a map using color-coded pixels that shows the origin of the particle through the heliosphereThe bubble-like region surrounding the solar system inflated by the solar wind, shielding the solar system from interstellar radiation. and its energetic level. Using the ToF sensor data, scientists like IMAP-LoThe IMAP-Lo instrument collects, counts, categorizes, and maps interstellar neutral atoms (ISN) and energetic neutral atoms (ENAs) of energies less than 40 kiloelectron volts (keV). IMAP-Lo is mounted on a pivot platform that allows it to adjust its field-of-view to capture data across almost the entire sky, and to measure interstellar neutral atoms throughout most of the year. lead Herb Funsten can also map the type, or species, of particle it was originally, helping us to understand in more detail the compositionThe specific components or “ingredients” that make up a substance or type of matter. of the heliosphere protecting our solar neighborhood. Comparing the data from IMAP-Hi and IMAP-Lo, scientists are better able to understand why some particles to accelerate as they journey through our solarhood.

Meet the Team  

The IMAP-Hi team is led by Herb Funsten and deputy leads Daniel Reisenfeld and Frederic Allegrini. The team consists of over 50 engineers and scientists collaboratively working together across four institutions: Los Alamos National Laboratory, Southwest Research Institute (SwRI), the University of New Hampshire, and the University of Bern, Switzerland. The team is comprised of a diverse spectrumElectromagnetic radiation arranged in order of wavelength. A rainbow is a natural spectrum of visible light from the Sun. Spectra are often punctuated with emission or absorption lines, which can be examined to reveal the composition and motion of the radiating source. of young to senior professionals and has a long history in the development of instruments that detect energetic neutral atomsAtoms with no charge that move very quickly. These atoms have equal numbers of positively-charged protons and negatively-charged electrons. ENAs form when charged particles from the solar wind travel outward and encounter atoms from the interstellar medium. Because the ENAs are neutral, they do not react to any magnetic fields. Some of these ENAs travel toward the inner solar system and are captured by the IMAP spacecraft. (ENAs) from the Earth’s magnetosphereThe region around a planetary body dominated by the planet’s magnetic interference. to the interstellar boundary.

My experience on IMAP has taught me a lot about working with people and how important it is to work together face-to-face. COVID was hard, and it was a tough setback for all of us on IMAP. I really now appreciate the magic that happens when you get a bunch of really smart engineers, scientists, and technicians in the same room. Zoom meetings come nowhere close. 

- Dan Reisenfeld, Deputy Lead, IMAP-Hi