NASA to Probe our Sun
“For the very first time, we’ll be able to touch, taste and smell our Sun.” (Lika Guhathakurta, Solar Probe Plus programme scientist at Nasa Headquarters in Washington DC)
Approaching as close as 3 RS above the Sun’s surface, Solar Probe will employ a combination of in-situ measurements and imaging to achieve the mission’s primary scientific goal: to understand how the Sun’s corona is heated and how the solar wind is accelerated.
The valuable data will be collected before the SPP – expected to cost around $180m (£120m) – is destroyed by the sun’s atmospheric temperature of 1 400C (2,550F). This sounds hot, but it is infinitesimal in comparison to the 15 million degrees at the sun’s core. Professor Harrison describes some of the difficulties of the mission:
“The Solar Probe will literally slice through a bit of the Sun’s atmosphere, and that’s never been done before… The real challenge will be making the measurements – you don’t want to just measure the effects that you’ve driven on the atmosphere [by the spacecraft]… It’s a bit like if you’re pushing a boat through a river and measuring something about the surface – you don’t want to measure the ripples from the boat. It’s a real challenge, but it’s something that is do-able.”
The SPP will be equipped with a range of instruments, including them a solar wind particle detector, a 3D camera, and a device which measures the magnetic field. For the instruments to even survive the initial temperatures and radiation, the probe will require a massive and complex carbon-composite protective shield. Here’s a more detailed diagram of the SPP. Good luck understanding it!
Scientists project that they will launch the SPP for before 2018.
Here are NASA’s stated Scientific Objectives:
Determine the structure and dynamics of the magnetic fields at the sources of the solar wind:
a. How does the magnetic field in the solar wind source regions connect to the photosphere and the
heliosphere?
b. How do the observed structures in the corona evolve into the solar wind?
c. Is the source of the solar wind steady or intermittent?
Trace the flow of the energy that heats the solar corona and accelerates the solar wind:
a. How is energy from the lower solar atmosphere transferred to and dissipated in the corona?
b. What coronal processes shape the non-equilibrium velocity distributions observed throughout the
heliosphere?
c. How do the processes in the corona affect the properties of the solar wind in the heliosphere?
Determine what mechanisms accelerate and transport energetic particles:
a. What are the roles of shocks, reconnection, waves, and turbulence in the acceleration of energetic particles?
b. What are the seed populations and physical conditions necessary for energetic particle acceleration?
c. How are energetic particles transported radially and across latitudes from the corona to the heliosphere?
Explore dusty plasma phenomena and their influence on the solar wind and energetic particle formation:
a. What is the dust environment of the inner heliosphere?
b. What is the origin and composition of dust in the inner heliosphere?
c. What is the nature of dust–plasma interactions and how does dust modify the spacecraft environment close to the Sun?
d. What are the physical and chemical properties of dust-generated
Below are some Solar wind observations collected by the Ulysses spacecraft during two separate polar orbits of the Sun, six years apart, at nearly opposite times in the solar cycle. Near solar minimum (left) activity is focused at low altitudes, high-speed solar wind prevails, and magnetic fields are dipolar. Near solar maximum (right), the solar winds are slower and more chaotic, with fluctuating magnetic fields. (Courtesy of Southwest Research Institute and the Ulysses/SWOOPS team)
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