NASA's CURIE Mission to Investigate the Sun's Radio Waves UPSC

NASA’S CURIE

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Context

NASA launched the CubeSat Radio Interferometry Experiment (CURIE) to study the origins of radio waves emanating from the Sun.
This mission, utilizing low frequency radio interferometry, aims to address the mysterious origins of solar radio emissions, particularly those linked to solar flares and coronal mass ejections (CMEs).

Details

Key Details

Aspect	Details
*Mission Name*	CubeSat Radio Interferometry Experiment (CURIE)
*Launch Date*	July 9, 2024
*Launch Vehicle*	ESA Ariane 6 rocket
*Launch Site*	French Guiana
*Technique*	Low frequency radio interferometry
*Spacecraft Design*	Two miniature spacecraft, no larger than a shoebox, orbiting approximately two miles apart
*Frequency Range*	0.1 to 19 megahertz (frequencies blocked by Earth's upper atmosphere)
*Orbit Altitude*	360 miles above Earth's surface
*Key Instruments*	Eight-foot antennas deployed by the spacecraft to detect and measure radio waves from the Sun

Mission Goals

Investigate Solar Radio Waves: CURIE aims to pinpoint the exact origin of radio waves within CMEs, a phenomenon observed decades ago but not fully understood.
Study Solar Flares and CMEs: By measuring radio waves linked to solar flares and CMEs, CURIE will enhance our understanding of these solar events and their impact on space weather.
Advance Radio Astronomy: CURIE's use of low frequency radio interferometry in space is a pioneering technique that could set the stage for future missions in radio astronomy.

Scientific and Technological Significance

Space Weather: Improved knowledge of solar radio waves can help predict and mitigate the effects of space weather on satellite communications and Earth-based technologies.
Pathfinder Mission: CURIE is considered a pathfinder for space-based radio astronomy, demonstrating innovative techniques that could be used in future scientific missions.
Enhanced Observations: Operating above Earth's atmosphere allows CURIE to measure radio frequencies that are otherwise blocked, providing clearer and more detailed data about solar emissions.

Sun's Radio Waves

The Sun is a prolific source of radio waves, emitting a wide range of frequencies that reveal much about its structure and activity.

Types of Solar Radio Emissions

Thermal Bremsstrahlung Emission:
- Produced when free electrons in the solar corona are deflected by ions, causing them to emit radiation.
- Main source of the Sun's quiescent radio emission, especially below 300 MHz due to typical coronal densities.
- Emission frequency relates to the electron density in the plasma.
Gyromagnetic Emission:
- Occurs when electrons spiral around magnetic field lines, resulting in emissions known as gyroresonance and gyrosynchrotron.
- Gyroresonance is prominent in the chromosphere, producing microwave radiation in the GHz range.
- Gyrosynchrotron is associated with microwave radio bursts from the chromosphere and coronal radio bursts.
Plasma Emission:
- Responsible for most solar radio bursts, originating from electron density oscillations (Langmuir waves).
- Accelerated by magnetic reconnection or shock waves, these bursts can exceed background radiation significantly.

Solar Radio Emission and Solar Activity

Quiet Sun Emission:
- Varies with frequency; higher frequencies originate closer to the photosphere while lower frequencies emanate from the corona.
- At very low frequencies, the Sun appears larger and brighter in radio images compared to its visible counterpart.
Active Regions and Sunspots:
- Sunspots and active regions emit strong radio waves, especially in the presence of solar flares.
- Radio emissions from sunspots are detectable even when they are not directly visible.

Solar Radio Bursts

Types of Radio Bursts:
- Classified based on duration and frequency characteristics, often associated with solar flares.
- Type I: Short events linked to continuous emission.
- Type II: Strong events with frequency shifts from high to low.
- Type III: Short, strong events with rapid frequency shifts.
- Type IV: Continuous emission lasting hours to days.
- Type V: Continuous emission at frequencies below 100 MHz, linked to Type III bursts.
Solar Flares and Radio Emission:
- Flares cause sudden, intense radio emissions due to the rapid acceleration of charged particles.
- Impulsive flares have short durations, while eruptive flares last longer and release more energy.

Observational Techniques

Radio Telescopes and Arrays:
- Instruments like the Nobeyama Radioheliograph, Very Large Array (VLA), and Low-Frequency Array (LOFAR) capture solar radio emissions across different frequencies.
- These observations help map the Sun's atmosphere and study solar activities in detail.

Types of Waves

Type of Wave	Description	Examples
*Mechanical Waves*	Require a medium to travel through (solid, liquid, or gas).	Sound waves, water waves, seismic waves
*Electromagnetic Waves*	Do not require a medium, can travel through a vacuum.	Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays
*Transverse Waves*	Particles of the medium move perpendicular to the direction of wave propagation.	Light waves, waves on a string, surface waves on water
*Longitudinal Waves*	Particles of the medium move parallel to the direction of wave propagation.	Sound waves, primary seismic waves (P-waves)
*Surface Waves*	Travel along the surface of a medium with particles moving in a circular motion.	Ocean waves, ripples on water
*Matter Waves*	Quantum mechanical description of particles exhibiting wave-like properties.	Electron waves, neutron waves
*Complex Waves*	Combination of transverse and longitudinal motions.	Tsunamis, Rayleigh seismic waves
*Torsional Waves*	Wave that twists around the axis of propagation.	Waves in bridges, skyscrapers, airplane wings

Types of electromagnetic waves, their properties, and applications:

Type of Wave	Wavelength Range	Frequency Range	Properties	Applications
*Radio Waves*	> 1 m	< 300 MHz	Long wavelengths, can penetrate through air, used for communication	Radio and TV broadcasting, wireless networking, navigation, MRI, radar systems
*Microwaves*	1 mm to 1 m	300 MHz to 300 GHz	Shorter wavelengths than radio waves, absorbed by water molecules	Cooking (microwave ovens), satellite communication, radar, WiFi, Bluetooth
*Infrared (IR)*	700 nm to 1 mm	300 GHz to 430 THz	Experienced as heat, emitted by warm objects	Remote controls, night-vision devices, thermal imaging, heaters, optical fiber communication
*Visible Light*	400 nm to 700 nm	430 THz to 750 THz	Detected by the human eye, various colors based on wavelength	Vision, photography, illumination, lasers, fiber optics
*Ultraviolet (UV)*	10 nm to 400 nm	750 THz to 30 PHz	Can cause skin tanning and burns, higher energy than visible light	Sterilization, fluorescent lights, UV tanning beds, detecting forgeries
*X-Rays*	0.01 nm to 10 nm	30 PHz to 30 EHz	Penetrate most materials, high energy	Medical imaging (X-rays), security scanners, cancer treatment
*Gamma Rays*	< 0.01 nm	> 30 EHz	Highest energy, can penetrate through most materials	Cancer treatment (radiotherapy), sterilizing medical equipment, astronomical observations

A short note on Sun

Category	Details
*Basic Information*
Names	The Sun is referred to as "Sol" in Latin and "Helios" in Greek mythology.
Age	Approximately 4.6 billion years old.
Distance from Earth	About 93 million miles (150 million kilometers).
*Physical Characteristics*
Type	G-type main-sequence star (G2V).
Diameter	About 865,000 miles (1.4 million kilometers).
Mass	Approximately 330,000 times the mass of Earth.
Composition	Mainly hydrogen (about 74%) and helium (about 24%), with trace amounts of heavier elements.
*Structure*
Core	The hottest part of the Sun, with temperatures reaching around 27 million °F (15 million °C). Nuclear fusion occurs here.
Radiative Zone	Surrounds the core, where energy is transferred outward by radiation.
Convection Zone	Above the radiative zone, where energy is transferred by convection.
Photosphere	The visible surface of the Sun, with temperatures around 10,000 °F (5,500 °C).
Chromosphere	Above the photosphere, visible during solar eclipses.
Corona	The outermost part of the Sun's atmosphere, extending millions of miles into space and with temperatures reaching up to 3.5 million °F (2 million °C).
*Orbit and Rotation*
Orbit	The Sun orbits the center of the Milky Way galaxy, taking about 230 million years for one complete orbit.
Rotation	The Sun rotates on its axis with a period of about 25 days at the equator and 36 days at the poles.
*Magnetic Activity*
Sunspots	Darker, cooler areas on the surface, associated with magnetic activity. The number of sunspots varies in an approximately 11-year cycle.
Solar Flares	Sudden, intense bursts of radiation caused by the release of magnetic energy.
Coronal Mass Ejections	Large expulsions of plasma and magnetic field from the Sun's corona that can impact Earth's magnetosphere.
Solar Wind	A stream of charged particles (mostly electrons and protons) emitted from the Sun's outer layers, traveling at about 450 km/sec.
*Future Evolution*
Red Giant Phase	In about 5 billion years, the Sun will expand into a red giant, engulfing the inner planets, including potentially Earth.
White Dwarf	Eventually, the Sun will shed its outer layers, leaving behind a dense, hot core that will cool over billions of years.
*Impact on Earth*
Light and Heat	Essential for life on Earth, driving weather patterns and photosynthesis.
Space Weather	Solar activity affects satellite operations, power grids, and communication systems.
Auroras	Interaction between solar wind and Earth's magnetic field causes auroras (Northern and Southern Lights).

Must read articles:

Structure of the Sun

Sources:

BusinessStandard

PRACTICE QUESTION

Q: Consider the following statements regarding the Sun:

The Sun's core is the region where nuclear fusion reactions convert hydrogen into helium, releasing vast amounts of energy.
The Sun's corona is the outermost layer of its atmosphere, which is hotter than the underlying photosphere.
The Sun's magnetic field is responsible for phenomena such as sunspots, solar flares, and coronal mass ejections.

Which of the statements given above is/are correct?

a) 1 and 2 only
b) 2 and 3 only
c) 1 and 3 only
d) 1, 2, and 3

Answer: d)