Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn...
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![Page 1: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/1.jpg)
Response of the magnetosphereand ionosphere
to solar wind drivers (including complexity)
Mervyn FreemanBritish Antarctic Survey
![Page 2: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/2.jpg)
The importance of Bz
• IMF Bz is a strong influence on many properties of the magnetosphere and ionosphere
• (and their space weather impacts)– electrical currents (GIC)– and electric field -> Joule heating (satellite drag)– particle precipitation (GNSS)– auroral oval location– geosynchronous magnetic field and energetic particles
(satellite anomalies)– etc
![Page 3: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/3.jpg)
The importance of Bz - currents
• IMF Bz is a strong influence on auroral electrojet index, AE– peak magnitude of large-scale currents– hourly averages [Newell et al., J. Geophys. Res., 2007]
![Page 4: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/4.jpg)
The importance of Bz - location
• IMF Bz is a strong influence on the latitude of auroral currents– cusp = poleward edge of auroral oval at noon (instantaneous)– Bs = Bz when Bz < 0, Bs = 0 otherwise (hourly average)
[Newell et al., J. Geophys. Res., 2007]
![Page 5: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/5.jpg)
Bz – not even half the answer
• IMF Bz explains only 37% of variance of the auroral electrojet index, AE– hourly averages– similarly for other quantities
[Newell et al., J. Geophys. Res., 2007]
![Page 6: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/6.jpg)
Not only Bz
• IMF By, B, and solar wind v (and n) also important• still explains only 69% of variance of the auroral electrojet index, AE
– hourly averages
)2/(sin 3/83/23/4 TBvdtd
[Newell et al., J. Geophys. Res., 2007]
![Page 7: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/7.jpg)
Not just about the solar wind
• magnetosphere and ionosphere produce the impact on satellites, power grids, etc, from the solar wind input
![Page 8: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/8.jpg)
Add some physics – models
• Prediction is no better than assuming the average value of the observations over the event, PE = 0 (- - -)
2
2mod
1obs
obs xxPE
• PE = 1 is perfect prediction
[Pulkkinen et al., J. Geophys. Res., 2010]
![Page 9: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/9.jpg)
[Pulkkinen et al., J. Geophys. Res., 2010]
![Page 10: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/10.jpg)
3 challenges
• Non-linearity – chaos
• Memory – substorms
• Turbulence – intermittency
![Page 11: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/11.jpg)
Non-linearity – chaos
• What is the sensitivity of the M-I response to uncertainties in the solar wind driver?
• How big and how quickly do errors grow?
![Page 12: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/12.jpg)
[Merkin et al., J. Geophys. Res., 2013]
![Page 13: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/13.jpg)
[Merkin et al., J. Geophys. Res., 2013]
![Page 14: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/14.jpg)
[Merkin et al., J. Geophys. Res., 2013]
LFM/Wind
![Page 15: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/15.jpg)
[Merkin et al., J. Geophys. Res., 2013]
LFM/THC
![Page 16: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/16.jpg)
[Merkin et al., J. Geophys. Res., 2013]
Ampere
![Page 17: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/17.jpg)
[Merkin et al., J. Geophys. Res., 2013]
![Page 18: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/18.jpg)
Memory – substorms
• Auroral electrojet index, AE, is influenced by past history of the IMF– 3-hour timescale, comparable to that of the substorm cycle
)2/(sin 3/83/23/4 TBvdtd
1
0
1 n
ii
i dtdwn
dtd
[Newell et al., J. Geophys. Res., 2007]
![Page 19: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/19.jpg)
Memory – substorms
• Simple integrate-and-fire model explains substorm timing statistically
• But not so well individually due to non-linearity
fff
E
Time
Onsets
[Freeman and Morley, Geophys. Res. Lett., 2004]
![Page 20: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/20.jpg)
Minimal substorm model
1. Solar wind power input at magnetopause P accumulates energy in magnetotail E.
2. Unique minimum energy state for magnetosphere F exists for given solar wind state P.
3. Magnetotail can only move to lower energy state F when energy threshold C is exceeded.
),( BvPdt
dE
)(PgCF
CEFE when
P
E
F
Time
[Freeman and Morley, Geophys. Res. Lett., 2004]
![Page 21: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/21.jpg)
Turbulence – intermittency
• Wilder fluctuations on short timescales
• Dependent on large-scale state[Consolini and de Michelis, Geophys. Res. Lett., 1998]
![Page 22: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/22.jpg)
Turbulence – intermittency
• Similar properties in space as well as time
• Wild fluctuations vary with spatial scale (and time scale)
[Consolini and de Michelis, Geophys. Res. Lett., 1998]
![Page 23: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/23.jpg)
3 solutions?
• Non-linearity, Memory, Turbulence challenges need:
• Models and Ensemble forecasting– represent evolving uncertainties from Sun to Earth
• Observations and Data assimilation– update prediction with latest information
• Scaling schemes– to handle unresolved scales and extremes
![Page 24: Response of the magnetosphere and ionosphere to solar wind drivers (including complexity) Mervyn Freeman British Antarctic Survey.](https://reader035.fdocuments.us/reader035/viewer/2022062716/56649e0c5503460f94af5034/html5/thumbnails/24.jpg)
Summary
• Bz is important• but ...
• it’s not even half the answer• magnetosphere and ionosphere produce the impact
from the solar wind input
• M-I observations, models, and research are just as vital