The chromosphere is cooler but denser than the corona.(AI-generated Image for representation/FreePik)Solar physicists will make a new attempt to observe the chromosphere of the sun, which is the most dynamic region. NASA, along with a team of international solar physicists, will launch a sounding rocket experiment on July 18 from New Mexico. Reddish in colour, the chromosphere is a region sandwiched between the sun’s atmosphere (the million-degree corona) and the photosphere (the sun’s visible surface). It is in the chromosphere where the solar flares, hot plasma jets, and powerful energy fluxes originate. The temperature variations recorded along this region can vary between 6000 degrees Celsius and over a million degrees Celsius. The suborbital sounding rocket experiment will last under ten minutes. On board will be the Solar EruptioN Integral Field Spectrograph (SNIFS) – a solar gazing spectrograph. a solar-gazing spectrograph solar gazing spectrograph.Also Read | Astronaut Shubhanshu Shukla’s return to India likely by mid-August, grand reception planned“SNIFS is a first-of-its-kind solar instrument and the first ultraviolet integral field spectrograph ever flown to study the Sun. It will observe a magnetically active region on the Sun and capture high-resolution spectroscopic data from both the chromosphere and the transition region — in real time,” Souvik Bose, co-investigator of the mission, told The Indian Express.The SNIFS stands out among the heliophysics missions to study the chromosphere, as scientists will now be able to obtain a full 2D field of view, along with being able to extract a complete spectrum for every pixel in that field, thus making it a 3D data set for each moment in time. SNIFS will target the hydrogen Lyman-alpha line — the brightest line in the solar ultraviolet spectrum and one of the most powerful diagnostics for upper chromospheric conditions.“From this, we can calculate temperatures, velocities, and densities of the solar plasma,” Bose said and further added, “It’s a dynamic, complex interface through which nearly all the energy that ultimately heats the corona must pass.” So, if we want to solve the long-standing puzzle of why the solar corona is so hot, we must first understand what is happening in the chromosphere.”The instrument comprises a Gregorian-style reflecting telescope, combined with a spectrograph via a specialised mirrorlet array that will focus on the light from each spatial location in the image. This is so that it may be spectrally dispersed without overlap from neighbouring locations. Story continues below this adAlso Read | LIGO-India construction to start in Hingoli this year; expected to be complete by 2030Solar physicists have noted the several challenges in observing the chromosphere and why this belt has remained elusive from detailed studies so far. Due to its composition, which is ionised plasma (a mix of charged and neutral particles), it behaves very differently in the presence of magnetic fields, and secondly, it does not adhere to the assumptions of thermodynamic equilibrium. Modelling the chromosphere has been an uphill task. But it is only an improved understanding of the chromosphere which will help scientists better understand the solar corona.The chromosphere is cooler but denser than the corona. “This means that the chromosphere rapidly loses energy and will need a continuous supply of energy in order to stay active. Only if there is an understanding of how this energy is supplied and dissipated will it help us piece together the larger story of how the solar corona is heated,” said Bose, who is currently a research scientist at the Lockheed Martin Solar & Astrophysics Lab in California.The main agencies involved in this mission are scientists from NASA’s Goddard Space Flight Center, the University of Colorado and Queen’s University Belfast, UK.© IE Online Media Services Pvt LtdTags:Sun