Undergraduate Physics Seminar Thanakorn Sukha 6105007 SCPY/B

Undergraduate Physics Seminar

Thanakorn Sukha 6105007 SCPY/BPhysics Department, Faculty of Science Mahidol University

9/7/2021 1

➢INTRO ➢Cosmic Rays and Interplanetary Electrons.➢Discovery of Jovian Electrons.

➢ Transport➢Solar Wind and Parker Spiral➢Earth-Jupiter Magnetic Field Connection

➢ Variation period➢13-month period and 27-day period.

➢Conclusion9/7/2021 2

OUTLINE

INTRO TRANSPORT VARIATION PERIOD CONCLUSIONS

9/7/2021 3

➢Energetic particles that

travel in space.

➢From outside and inside

the solar system.

➢1H+, 4He2+, 12C+, 16O8+,…,

𝛾 , 𝜇+,…,

https://www.esa.int/Enabling_Suppo

rt/Space_Engineering_Technology/ES

A_missions_team_up_to_map_cosmic

_rays_across_Solar_System


Cosmic Rays

➢Interplanetary energetic electrons:

➢Solar electrons

➢from the Sun

➢Galactic electrons

➢from outside solar system

➢Jovian electrons

➢from Jupiter9/7/2021 4


InterplanetaryElectrons

9/7/2021 5

➢Strange Phenomenal at the Solar minimum

➢Pioneer 10


9/7/2021 6

➢Solar Cycle :

➢Cycles of solar

(magnetic) activity.

➢Sunspot.

➢~11 years.

➢ Solar maximum

➢ Solar minimum


Solar Cycle

https://spaceweather.com/glossary/

images2009/zurich.gif

https://www.esa.int/Science_Exploration/Space_Science/

Space_for_you/Massive_sunspot_faces_Earth

➢Unusual detection in

low-energy electrons

at Solar minimum.

9/7/2021 7

McDonald et al. 1972


Electrons atNear-Earth Orbit

➢Solar electrons?

➢Galactic electrons?

➢Spectral index is different

➢𝛾 ~ 1.5(galactic electron 𝛾 ≥ 2.5 − 3)

9/7/2021 8Lin, Anderson, & Cline, 1972


Electrons atNear-Earth Orbit

9/7/2021 9

➢A space mission. Did a

flyby of Jupiter in 1973.

➢Confirmed Jupiter

is emitting MeV range

electrons.

https://www.nextwider.com/wp-

content/uploads/2017/06/pioneer-10.jpg


Pioneer 10

9/7/2021 10


9/7/2021 11

➢Strong :

➢40 times geomagnetic.

➢Electrons are trapped

and accelerated by Jupiter’s

magnetosphere.


Jovian Magnetosphere

9/7/2021 12

➢The spectral index of

Jupiter’s electrons

is 𝛾 ~ 1.5

Teegarden at al., 1974

.

.


Evidence To Believe

9/7/2021 13


But…Electrons

from Jupiter

to

the Earth?

9/7/2021 14

➢Solar Wind and Interplanetary Magnetic Field.➢Parker Spiral.

➢Earth-Jupiter Magnetic Field Connection.


9/7/2021 15

➢Solar wind :

➢Plasma released from

the sun, continuously.➢Moving charge ⇔ Magnetic field

https://www.sciencenews.org/wp-

content/uploads/2017/12/121817_LG_corona_feat.jpg


Solar Wind

➢The sun is rotating.

➢Interplanetary

magnetic field(IMF)

has spiral shape.

➢called Parker Spiral.

9/7/2021 16Moses, 1986


Parker Spiral

➢Solar wind speed

≈ 450 km/s

➢Not constant.

➢The density of the

spiral is not

uniform.

9/7/2021 17Moses, 1986


Parker Spiral

9/7/2021 18


And that is the .

Charged particles travel

.

9/7/2021 19

➢Electrons propagate along the

interplanetary magnetic field

line.


Jovian Electrons

Moses, 1986

9/7/2021 20Baker et al., 1996


Earth-JupiterMagnetic field connection

➢when the field line

connect Earth and

Jupiter, we can

observe Jovian

electrons.

9/7/2021 21

𝑩𝒗 = 𝒗⊥ 𝑩 + 𝒗∥𝑩

𝒗∥𝑩

𝒗⊥ 𝑩

𝒗

𝒊


Charged particle in magnetic field line

9/7/2021 22

𝑟𝑔 =𝑚𝑣⊥|𝑞|𝐵

➢Electrons’ gyroradii ~300 km.

➢Low chance of energy loss.

➢The characteristic of electrons at

Jupiter and Earth are identical.


Gyroradius

9/7/2021 23

➢Strange electron flux near Earth.

➢ Jupiter emitting electrons.

➢Electron trave along IMF

➢ Solar wind create IMF

➢E-J magnetically connected, can

observe at earth.


Before weMove on

9/7/2021 24

➢13-Month Period

➢27-Day Period


9/7/2021 25

Logachev et al. 2020


9/7/2021 26

➢Synodic period of Jupiter

≈ 13 month➢Sun, Earth, Jupiter are at the

same angular configuration

every 13 month.


13-Month

9/7/2021 27


But… Can the Field

Connect E-J at

?

9/7/2021 28

At the

beginning

Of cycles

[low flux]

At the

middle of

cycle

[high flux]Logachev et al. 2020


9/7/2021 29

➢The most favorable

conditions.➢Solar wind speed :

450 ± 50 km/s

➢Earth-Jupiter angle :

230 ± 20 deg



13-Month

9/7/2021 30

➢The sun rotation:

➢ ~27 days



27-Day

9/7/2021 31

➢In 1 rotation (360deg)➢Only 1 segment

make good connect

Earth and Jupiter.

➢OR, we could say it

depends on solar wind

speed.


27-Day


9/7/2021 32

➢Right time, Right place.➢ Solar wind speed(IMF)

➢ Earth-Jupiter angular distance

➢All for E-J .


Right place,Right time.

9/7/2021 33

➢Jovian electrons, one of interplanetary

electrons.

➢Jupiter emitting MeV range electrons.

➢We can observe Jovian electrons when the Earth

and Jupiter are connected by IMF.

➢Solar wind play an important role.

INTRO TRANSPORT VARIATION PERIOD

CONCLUSIONS

Conclusions

9/7/2021 34

Logachev, Y. I., Daibog, E. I., & Kecskeméty, K. (2021). Jovian electrons at the

Earth orbit and stationary structures in the solar wind. Monthly Notices of

the Royal Astronomical Society, 502(2), 2541–2548.

https://doi.org/10.1093/mnras/staa2782

McDonald, F. B., Cline, T. L., & Simnett, G. M. (1972). Multifarious temporal

variations of low-energy relativistic cosmic-ray electrons. Journal of

Geophysical Research, 77(13), 2213–2231.

https://doi.org/10.1029/ja077i013p02213

Moses, D. (1987). Jovian electrons at 1 AU - 1978–1984. The Astrophysical

Journal, 313, 471. https://doi.org/10.1086/164987

Teegarden, B. J., McDonald, F. B., Trainor, J. H., Webber, W. R., & Roelof, E.

C. (1974). Interplanetary Mev electrons of Jovian origin. Journal of

Geophysical Research, 79(25), 3615–3622.


References

https://doi.org/10.1093/mnras/staa2782


https://doi.org/10.1086/164987


9/7/2021 35

➢Corotating interaction region

➢Region of compress solar wind plasma.

9/7/2021 36

9/7/2021 37


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Undergraduate Physics Seminar Thanakorn Sukha 6105007 SCPY/B