About: About blog posts
Browse by time:
- July 2022 (1)
- May 2022 (1)
- April 2022 (3)
- March 2022 (2)
- February 2022 (3)
- January 2022 (2)
- December 2021 (4)
- November 2021 (2)
- September 2021 (6)
- August 2021 (1)
- July 2021 (7)
- June 2021 (2)
- May 2021 (5)
- April 2021 (3)
- March 2021 (7)
- February 2021 (5)
- January 2021 (4)
- December 2020 (7)
- November 2020 (12)
- October 2020 (13)
- September 2020 (11)
- August 2020 (14)
- July 2020 (17)
- June 2020 (18)
- May 2020 (12)
- April 2020 (14)
- March 2020 (15)
- February 2020 (13)
- January 2020 (7)
- December 2019 (6)
- November 2019 (11)
- October 2019 (15)
- September 2019 (14)
- August 2019 (4)
- July 2019 (10)
- June 2019 (5)
- May 2019 (8)
- April 2019 (5)
- March 2019 (13)
- February 2019 (5)
- January 2019 (10)
- December 2018 (5)
- November 2018 (9)
- October 2018 (13)
- September 2018 (12)
- August 2018 (6)
- July 2018 (5)
- June 2018 (9)
- May 2018 (5)
- April 2018 (9)
- March 2018 (14)
- February 2018 (16)
- January 2018 (7)
- December 2017 (5)
- November 2017 (8)
- October 2017 (11)
- September 2017 (10)
- August 2017 (9)
- June 2017 (16)
- May 2017 (14)
- April 2017 (6)
- March 2017 (6)
- February 2017 (4)
- January 2017 (11)
- December 2016 (5)
- November 2016 (13)
- October 2016 (7)
- September 2016 (11)
- August 2016 (6)
- July 2016 (19)
- June 2016 (12)
- May 2016 (11)
- April 2016 (11)
- March 2016 (13)
- February 2016 (17)
- January 2016 (10)
- December 2015 (5)
- November 2015 (15)
- October 2015 (19)
- September 2015 (18)
- August 2015 (23)
- July 2015 (32)
- June 2015 (17)
- May 2015 (23)
- April 2015 (28)
- March 2015 (23)
- February 2015 (19)
- January 2015 (17)
- December 2014 (26)
- November 2014 (42)
- October 2014 (33)
- September 2014 (30)
- August 2014 (16)
- July 2014 (27)
- June 2014 (37)
- May 2014 (19)
- April 2014 (14)
- March 2014 (35)
- February 2014 (30)
- January 2014 (28)
- December 2013 (25)
- November 2013 (30)
- October 2013 (41)
- September 2013 (48)
- August 2013 (36)
- July 2013 (44)
- June 2013 (39)
- May 2013 (29)
- April 2013 (36)
- March 2013 (35)
- February 2013 (31)
- January 2013 (48)
- December 2012 (20)
- November 2012 (29)
- October 2012 (48)
- September 2012 (30)
- August 2012 (16)
- July 2012 (32)
- June 2012 (27)
- May 2012 (26)
- April 2012 (25)
- March 2012 (30)
- February 2012 (35)
- January 2012 (25)
- December 2011 (23)
- November 2011 (41)
- October 2011 (31)
- September 2011 (29)
- August 2011 (23)
- July 2011 (24)
- June 2011 (18)
- May 2011 (3)
Browse by author:
- rss Bo Peng (1)
- rss Yisheng (26)
- rss aanand6 (20)
- rss adebrech (151)
- rss afrank (30)
- rss aliao (6)
- rss alipnicky (2)
- rss amyzou (54)
- rss aquillen (1)
- rss blin (18)
- rss bliu (270)
- rss bpeng6 (7)
- rss brockjw (7)
- rss bshroyer (6)
- rss ceh5286 (2)
- rss dnp19 (7)
- rss ehansen (290)
- rss elambrid (12)
- rss erica (280)
- rss esavitch (43)
- rss fschmidt (35)
- rss gguidarelli (4)
- rss idilernia (35)
- rss johannjc (245)
- rss lchamandy (104)
- rss likuntian (5)
- rss lsabin (2)
- rss madams (61)
- rss martinhe (76)
- rss mblank (30)
- rss mccann (3)
- rss mehr (16)
- rss noyesma (6)
- rss rmarkwic (20)
- rss shuleli (146)
- rss smurugan (24)
- rss yirak (4)
- rss ytlee (1)
- rss zchen (165)
Browse by category:
- rss Accretion (1)
- rss Bonner-Ebert (1)
- rss Bvn (1)
- rss CollidingFlows (27)
- rss Disks (1)
- rss FieldLoop (1)
- rss Magnetic-tower (1)
- rss Meeting-outline (1)
- rss RAID (1)
- rss RT (1)
- rss Resistive_MHD (1)
- rss Test (1)
- rss alfalfa (3)
- rss animation (1)
- rss bamboo (2)
- rss bipolar (1)
- rss bluehive2 (1)
- rss bluestreak (3)
- rss cameraobjects (6)
- rss clover (1)
- rss clump (4)
- rss cooling (1)
- rss data-management (4)
- rss development (1)
- rss disks (3)
- rss documentation (15)
- rss dust (32)
- rss gpu (1)
- rss grass (2)
- rss hydrostatic (1)
- rss mGlobal (1)
- rss magnetic-field (1)
- rss mass (2)
- rss movies (1)
- rss mx (1)
- rss nebula (1)
- rss notification (1)
- rss others-research (1)
- rss outreach (1)
- rss parameter (1)
- rss plugins (1)
- rss query (1)
- rss scaling (1)
- rss script (1)
- rss shape (3)
- rss sinks (1)
- rss stampede (2)
- rss streamlines (2)
- rss study (1)
- rss tasks (7)
- rss testing (6)
- rss ticketchart (1)
- rss tutorial (1)
- rss visit (4)
- rss visualization (3)
- rss vnc (1)
- rss vpn (3)
- rss w00t (1)
- rss wind (4)
- rss wind-capture (1)
Notes from today's meeting with Jim Kasting
Background
- Habitable zone limited near by by runaway greenhouse at 1 AU and limited far away by the Maximum CO2-H2O greenhouse effect at 1.8 AU
- With H2 green house gas you can extend out to 10 AU (3 M_earth with 40 bars of H2 atm)
- Homopause (turbopause) at 100 km - where turbulent mixing ceases and atmosphere is not well mixed. Transport of hydrogen governed by molecular diffusion
- Exopause at 500 km - where gas becomes collisionless and fast moving hydrogen particles can escape. Velocity distribution no longer Boltzmann. Rate governed by Jeans evaporation rate.
- On Earth, exopause is fairly warm - and Jeans evaporation is quick - so H2 loss rate controlled by diffusion through the Homopause
- On early Mars, the exopause is colder and therefore Jeans evaporation is slower and might have been responsible for regulating H2 loss. Going from 1D to 2D reduced jeans evaporation rate by ~4 which could increase the steady state H2 concentration to the 20% needed to create enough of a green house effect to place early Mars in the habitable zone - and explain the fluvial features on Mars.
Goal
Calculate an upper limit on the escape rate from the Exopause and show that it is lower than the diffusion limit and hopefully consistent with the 20% concentration necessary to explain the fluvial features on Mars
Complexities of the physical model
- Geometry - Obliquity, magnetic fields,
- Multi-species
- Chemistry
- diffusion
- non-Lte
- heating and cooling
- multi-line
- collisionless - moment equations from the boltzmann equation
Possible simulations
- 1D - 2 fluid with most of the physics (apply an approximation to model the moments of the velocity distribution where it becomes collisionless) to demonstrate the h2 loss rate < diffusion limit
- Evenly spaced in log altitude (not radius)?
- 3 points per pressure scale height
- multi-fluid?
- diffusion
- line transfer - would need multi-bin line transfer
- cooling
- equation of state
- Redo Stone and Proga in 3D and measure the Jeans evaporation rate.
- MHD
- rotation
- Posted: 11 years ago
- Author: Jonathan
- Categories: (none)
Comments
No comments.