Application of Magnetospheric Imaging Techniques to Global Substorm Dynamics


The IMAGE mission will address the above objectives in unique ways using both existing and new imaging techniques. IMAGE will make use of two new observing techniques to accomplish its mission. The first technique is radio plasma imaging (RPI), which senses plasma densities between 0.1 and 105 cm-3 and images plasma boundaries globally throughout the magnetosphere on a several-minute time scale. Thus, for example, the global configuration of the magnetopause and the structure of its interior boundary layer will be imaged continuously as they respond to changes in the solar wind and interplanetary magnetic field.

The second new technique employed by IMAGE is neutral atom imaging (NAI) at energies from 10 eV to 200 keV. NAI consists of three separate instruments because the physical processes that convert the incoming neutral atoms to ions and then detect the ions differ over the three energy regimes (< or equal to 1 keV, 1-30 keV, 10-200 keV). The NAI suite of instruments will also provide enrgy and composition- resolved images with a time resolution of 300 s. The low energy coverage of NAI (up to 300 eV) is essential for observing the quantity of ionospheric ions injected into the magnetosphere during specific substorm phases. High energy NAI observations will be used to monitor the intensity and spatial distribution of the ring current and high energy plasma distributions in the inner magnetosphere characterizing an entire storm period.

Table 1: IMAGE instrument characteristics.

Finally, IMAGE will also use two optical imagers in the far ultraviolet (FUV), in the wavelength range of 121-160 nm, and in the extreme ultraviolet (EUV) at 30.4 nm to image the auroral zone, geocorona, and the plasmasphere (by resonance He+ emission). The FUV auroral observations will enable the observations from the IMAGE instruments to be placed in context with the appropriate substorm phase. Table 1 summarizes the IMAGE instruments characteristics.

In the following sections, we will concentrate on discussing how the NAI, radio, and other imaging measurements from IMAGE will enable the development of a global view of the substorm process.

Web page prepared by:
Dan Isaac,

Date: February 28, 1997