2. • Mirror instability is one of three
magnetohydrodynamic instabilities that
occur in the presence of pitch angle
anisotropies in a uniform plasma.
• Hasegawa [1969] paper theorized an
inhomogeneous form which he called
the drift mirror instability, which can be
observed when the criterion
Γ = 1 + 𝑖 𝛽⊥𝑖 1 −
𝑇⊥𝑖
𝑇∥𝑖
< 0 is met.
• Once the perpendicular pressure reaches
a certain threshold, the diamagnetic
plasma expels the magnetic field,
moving to areas of low magnetic
pressure, converting perpendicular
motion to parallel.
• Southwood [1993] posits that the
instability only occurs when 𝛽⊥ is greater
than unity.
Center for
Solar-Terrestrial
Research
[Southwood and Kivelson, 1993]
21. Questions
• What causes such a sharp depletion of
particles?
• Why are the high energy/field aligned
particles effected more?
• Do particles cause the wave, or does the wave
cause the particle fluctuations?
Center for
Solar-Terrestrial
Research
24. Center for
Solar-Terrestrial
Research
An optimal Kaiser 𝛽
parameter and number
of taps is calculated with
SciPy’s kaiserord, with a
width of 0.001/nyq_rate,
and ripple dB of 50.
A FIR filter is
computed using
SciPy’s firwin, with a
period range of 2 – 4
minutes.
The filter is applied
with SciPy’s filtfilt,
which convolutes
forward, and then
backward, to avoid
phase shift.
Notes de l'éditeur
Showing 180 keV in unfiltered flux to demonstrate drop. Lower energies are more resonant. Isolated counts are not visible. Bandpass filter: 2-4 minutes. Oscillation is ≈ 2.5 minutes.
Less particles at higher energies, wave less visible
Missing data for PA=7.5 in PH, no missing data in E
This shows the average field aligned energy goes up, and the average anti-field aligned goes down. Lower energies don’t’ see this in B.
Lower energies see it in A
Need to examine wave propagation direction, other ion species, ion cyclotron instability competition,
![• Mirror instability is one of three
magnetohydrodynamic instabilities that
occur in the presence of pitch angle
anisotropies in a uniform plasma.
• Hasegawa [1969] paper theorized an
inhomogeneous form which he called
the drift mirror instability, which can be
observed when the criterion
Γ = 1 + 𝑖 𝛽⊥𝑖 1 −
𝑇⊥𝑖
𝑇∥𝑖
< 0 is met.
• Once the perpendicular pressure reaches
a certain threshold, the diamagnetic
plasma expels the magnetic field,
moving to areas of low magnetic
pressure, converting perpendicular
motion to parallel.
• Southwood [1993] posits that the
instability only occurs when 𝛽⊥ is greater
than unity.
Center for
Solar-Terrestrial
Research
[Southwood and Kivelson, 1993]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)