Interplanetary magnetic correlation and low-frequency spectrum over many solar rotations

Area of Science:

• Space Physics
• Plasma Physics
• Solar Physics

Background:

• Solar wind fluctuations across various scales are crucial for understanding plasma turbulence and cosmic ray transport.
• Previous studies focused on frequencies within the Kolmogorov inertial range, leaving low-frequency phenomena less explored.

Purpose of the Study:

• To investigate the properties of low-frequency solar wind fluctuations, particularly the power-law spectrum and solar rotation signatures.
• To explore the relationship between these spectral features and their potential origin in the solar dynamo.

Main Methods:

• Utilized decade-long interplanetary data, performing correlation analysis to study fluctuations at long time scales (low frequencies).
• Analyzed data based on wind speed, solar cycle phase, and magnetic field components.
• Examined the [Formula: see text] spectral signature and point spectral features related to solar rotation.

Main Results:

• Observed a [Formula: see text] spectral signature at frequencies well below the Kolmogorov inertial range.
• Found that solar rotation harmonics exhibit power consistent with an extension of the [Formula: see text] spectrum down to approximately [Formula: see text].
• The broadband [Formula: see text] spectrum was present across different solar wind types.

Conclusions:

• The power-law spectrum in the solar wind extends to remarkably low frequencies, encompassing solar rotation harmonics.
• The consistent presence of the [Formula: see text] spectrum suggests it may originate from, or be related to, the solar dynamo.
• This finding provides new insights into the generation mechanisms of large-scale solar wind structures.