SLIDE 1
H y p e r v e l
- c
i t y D u s t I m p a c t s
- n
t h e W i n d S p a c e c r a f t
Stephanie Wood
David Malaspina & Laila Andersson
t s u D y t i c o l e d v n r i e W p e y H h - - PowerPoint PPT Presentation
t s u D y t i c o l e d v n r i e W p e y H h - - PowerPoint PPT Presentation
Stephanie Wood David Malaspina & Laila Andersson t s u D y t i c o l e d v n r i e W p e y H h t n o s t c a t p f a m r c I e c a p S E } Lots of dust- U S } Not just in Solar System S
SLIDE 2
SLIDE 3
M E T H O D
} Characterize our
surroundings (Local Interstellar Cloud)
} Distinguishing between
interstellar dust (ISD) from interplanetary dust (IPD)
} Relationship between
dust and solar cycle
SLIDE 4
W H Y S H O U L D W E C A R E ?
} Gain further
understanding of our spot in the galaxy
} How the Solar System
formed
} Exoplanets and stars } Knowledge of dust =
} Prediction of damage to
spacecraft
SLIDE 5
W O U N D E D I N T H E F I E L D
c
- m
e t a r y cometary
SLIDE 6
M Y P A R T
} Get as much data as I
can from Wind
} Sift through to find dust
impacts
} Determine:
} Direction } Flux } Appearance over solar
cycle
SLIDE 7
WHAT IS WIND?
} 1994 – Present } Sits at L1 – in front of earth
equal gravitational pull from Earth-Sun System
} Measures electric field } Original mission:
} Study the solar wind before
Earth
} BUT after damage due to
dust hit…
} Can better see dust impacts on
body
} Dust on impact plasma
SLIDE 8
WHAT IS DUST?
} ISD
} At 1 AU = ~0.3µm } m ~ 2.8 x 10-16 kg
} IPD
} Meteoroids m > 10-8 kg } β-meteoroids
10-18<m<10-15 kg
} Nanodust m < 10-18 kg
SLIDE 9
O T H E R D I F F E R E N C E S
} ISD velocity ~ 26 km/s
} ~20 yrs. to travel Solar
System
} IPD velocity ~ 30 km/s } Charge release is similar
(qr = m/v3/2)
} Limited by spacecraft
} Saturates at 300 mV/m
} Distinguish between IPD
and ISD by direction
SLIDE 10
W H A T W E E X P E C T E D
} Tried to find correlation with
interstellar dust (ISD) flux and solar cycle
} Less ISD at solar maximum
with stronger magnetic fields
} More ISD at solar minimum } But with speed of ISD, maybe
just trend over longer time period
} Monthly modulation } Max # ISD impacts in March } Least # ISD impacts in August
SLIDE 11
SLIDE 12
D A T A
} Comes in ascii file
} Electric Field
Measurements
} Taken every 17 ms , 1
month
} Selected by amplitude –
~100 highest amp/day
} Convert to idlsave file } FIND DUST!
SLIDE 13
Accuracy of my dust finding algorithm: 97.6%
SLIDE 14
W H A T D O I W I T H A L L T H A T ?
} Calculate direction and
flux
} Month } Year
SLIDE 15
DIRECTION
SLIDE 16
SLIDE 17
M O N T H L Y
SUN EARTH ISD Direction v
SLIDE 18
Y E A R L Y
SLIDE 19
M A T C H I N G W I T H U L Y S S E S
} Not much dust seen until
~2000
} Still see low point in ‘99
Kellogg, Paul. University of Minnesota. July 12, 2013.
SLIDE 20
} Same direction of origin seen
Horányi, Mihaly. “iDUST: Dust Tomography of the Heliosphere.” PowerPoint Presentation. Lunar Science Forum. 2011.
SLIDE 21
ULYSSES TRAJECTORY
Horányi, Mihaly. “iDUST: Dust Tomography of the Heliosphere.” PowerPoint Presentation. Lunar Science Forum. 2011.
SLIDE 22