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X-ray Beam Induced Current Measurements for Multi-Modal X-ray Microscopy of Solar Cells
Published on: August 20, 2019
Evidence for Alfvén waves in solar x-ray jets
J W Cirtain1, L Golub, L Lundquist
1Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA. Jonathan.W.Cirtain@nasa.gov
Science (New York, N.Y.)
|December 8, 2007
Summary
New observations reveal numerous high-speed X-ray jets originating from polar coronal holes. These dynamic events, occurring frequently, may significantly contribute to the high-speed solar wind.
Area of Science:
- Solar Physics
- Plasma Astrophysics
- Space Weather
Background:
- Coronal magnetic fields are highly dynamic, undergoing processes like magnetic reconnection.
- Magnetic reconnection can release significant energy, leading to phenomena such as solar flares, coronal mass ejections, and smaller-scale X-ray jets.
- Previous observations of X-ray jets had documented lower event rates and speeds.
Purpose of the Study:
- To investigate the characteristics and frequency of X-ray jets in polar coronal holes.
- To determine the velocities and dimensions of these observed X-ray jets.
- To assess the potential contribution of X-ray jets to the solar wind.
Main Methods:
- Utilized Hinode observations of polar coronal holes.
- Detected and analyzed X-ray jet events.
- Measured jet velocities, dimensions, and durations.
Main Results:
- Discovered X-ray jets with two distinct velocity populations: near Alfvén speed (~800 km/s) and near sound speed (200 km/s).
- Observed a significantly higher frequency of events, averaging 10 per hour, compared to previous reports.
- Characterized jets as 2 x 10^3 to 2 x 10^4 km wide, 1 x 10^5 km long, and lasting 100-2500 seconds.
Conclusions:
- The high number and velocities of X-ray jets suggest they are a common and energetic phenomenon.
- These findings indicate that X-ray jets likely play a crucial role in accelerating and contributing to the high-speed solar wind.
- Further research is warranted to fully understand the implications of these jets for solar wind dynamics and space weather.
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