Re-evaluation of thermosphere heating by solar EUV and UV radiation <sup>1</sup>This article is part of a Special issue that honours the work of Dr. Donald M. Hunten FRSC who passed away in December 2010 after a very illustrious career.
Bibliographic record
Abstract
This paper presents a new calculation of neutral gas heating by solar extreme ultraviolet and ultraviolet radiation with updated solar irradiances and photochemistry. It is found that the heating rate of the neutral gas is significantly different from some previous determinations. Neutral gas heating arises from the many exothermic chemical reactions that take place from the ions and excited species created by energetic electrons. The calculations show that less than half the energy initially deposited ends up heating the neutral gases. The rest is radiated or lost in the dissociation of O2 because the O atoms do not recombine in the thermosphere above 100 km. At high altitudes, the heating rates are sensitive to the thermal electron density and long-lived species. The calculations show that, while most of the energy is deposited at low altitudes, the heating per neutral particle is greatest at high altitudes. This paper also examines the consequences of different thermal electron cooling rates to O2 vibration and O fine structure. Although there are large differences between the individual rates, the overall cooling rates have similar magnitudes and there is little effect on the calculated electron temperature. The concept of the neutral gas heating efficiency is a useful way of capturing the flow of energy in the thermosphere and was used in early global models to reduce computation. It is defined at a particular altitude as the rate of energy transferred to the neutral gas divided by the energy deposited rate at that altitude. The heating efficiency peaks at about 0.5 just below 200 km altitude. The heating efficiency is relatively insensitive to the solar input and thermosphere conditions when plotted against pressure rather than altitude coordinates and when thermal electron heating is calculated separately.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".