ISRO Missions and Discoveries

PAPA: Plasma Analyser Package for Aditya L1


From UPSC perspective, the following things are important :

Prelims level: PAPA, Aditya L1, CMEs

Mains level: NA



  • India’s pioneering solar mission, Aditya-L1, has achieved a significant milestone as advanced sensors onboard successfully detected the impact of coronal mass ejections (CMEs), marking a leap forward in space exploration.

 Coronal Mass Ejections (CMEs)

  • CMEs were discovered in 1971 and established their importance in solar-terrestrial relations later in the 1980s.
  • It consists of massive clouds of solar plasma and magnetic field lines.
  • It typically accompanies solar flares and filament eruptions.
  • The frequency of CMEs varies with the 11-year solar cycle, with about one a week observed during solar minimum and an average of two to three CMEs per day observed near solar maximum
  • They travel at thousands of km per hour.
  • They can lead to geomagnetic storms, aurorae, and in extreme cases, damage to electrical power grids.
  • They are primarily detected using coronagraphs aboard spacecraft such as SOHO and STEREO.
  • Not all CMEs interact with Earth, but those that do can cause disruptions to satellite communications and power grids.
  • Halo CMEs are Earth-directed CMEs visible as rings in white-light coronagraph observations.

About Plasma Analyser Package for Aditya (PAPA)

  • Purpose: PAPA is an energy and mass analyser tailored for in-situ measurements of solar wind electrons and ions within the low energy range.
  • Sensor Composition: PAPA comprises two sensors—Solar Wind Electron Energy Probe (SWEEP) and Solar Wind Ion Composition Analyser (SWICAR)—facilitating comprehensive observations of solar phenomena.
  • Functionalities: Sensors not only measure electrons and ions’ energy but also ascertain their direction of arrival, enabling a holistic understanding of solar wind dynamics.

CME Detection and Analysis

  • Observations: PAPA detected CME events, notably on December 15, 2023, and during February 10-11, 2024.
  • December 15, 2023: Single CME event marked by a sudden increase in electron and ion counts, aligning with solar wind parameters and magnetic field measurements.
  • February 10-11, 2024: Multiple minor CME events observed, showcasing nuanced variations in electron and ion counts over time.

Performance Evaluation and Continuous Observations

  • PAPA sensors are currently operational in default mode, demonstrating adherence to design specifications across all operational modes.
  • Continuous observations underscore PAPA’s efficacy in monitoring space weather conditions and its adeptness in detecting and analyzing solar phenomena.

Back2Basics: Aditya-L1

  • Launched successfully by ISRO on September 2.
  • Orbits around the Lagrangian Point 1 (L1), maintaining a stable position 1.5 million km from Earth in the direction of the Sun.
  • Hosts seven payloads dedicated to studying various aspects of the Sun, encompassing both remote observations and in-situ measurements.

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